An Introduction to Radar Data in Pangeo Using Xradar + Py-ART

---

Overview

If you have an introductory paragraph, lead with it here! Keep it short and tied to your material, then be sure to continue into the required list of topics below,

1. Introduction to Py-ART 1.0

2. Introduction to xradar

3. The power of common data models

4. Visualization fun

Prerequisites

Concepts	Importance	Notes
Introduction to Xarray	Necessary	Familiarity with data model
Py-ART Basics	Necessary	Familiarity with data model
Understanding of NetCDF	Helpful	Familiarity with metadata structure
Comet/MetEd Radar Fundamentals	Helpful	Familiarity with radar science

• Time to learn: estimate in minutes. For a rough idea, use 5 mins per subsection, 10 if longer; add these up for a total. Safer to round up and overestimate.

• System requirements:

  • Populate with any system, version, or non-Python software requirements if necessary

  • Otherwise use the concepts table above and the Imports section below to describe required packages as necessary

  • If no extra requirements, remove the System requirements point altogether

---

Imports

Begin your body of content with another --- divider before continuing into this section, then remove this body text and populate the following code cell with all necessary Python imports up-front:

import pyart
from open_radar_data import DATASETS
import xradar as xd
import xarray as xr
import hvplot.xarray
import holoviews as hv
import cartopy.crs as ccrs
import cmweather
import wradlib

hv.extension("bokeh")

## You are using the Python ARM Radar Toolkit (Py-ART), an open source
## library for working with weather radar data. Py-ART is partly
## supported by the U.S. Department of Energy as part of the Atmospheric
## Radiation Measurement (ARM) Climate Research Facility, an Office of
## Science user facility.
##
## If you use this software to prepare a publication, please cite:
##
##     JJ Helmus and SM Collis, JORS 2016, doi: 10.5334/jors.119

An Introduction to Py-ART 1.0

This is where you begin your first section of material, loosely tied to your objectives stated up front. Tie together your notebook as a narrative, with interspersed Markdown text, images, and more as necessary,

Read in Data, Load into the Radar Object

Here, we use a sample file from a radar used for a field campaign in the Colorado Rockies!

file = DATASETS.fetch("gucxprecipradarcmacppiS2.c1.20220314.021559.nc")
file

Downloading file 'gucxprecipradarcmacppiS2.c1.20220314.021559.nc' from 'https://github.com/openradar/open-radar-data/raw/main/data/gucxprecipradarcmacppiS2.c1.20220314.021559.nc' to '/home/runner/.cache/open-radar-data'.

'/home/runner/.cache/open-radar-data/gucxprecipradarcmacppiS2.c1.20220314.021559.nc'

radar = pyart.io.read(file)
radar

/home/runner/miniconda3/envs/open-radar-pangeo-showcase-2024-dev/lib/python3.10/site-packages/pyart/io/cfradial.py:412: UserWarning: WARNING: valid_min not used since it
cannot be safely cast to variable data type
  data = self.ncvar[:]
/home/runner/miniconda3/envs/open-radar-pangeo-showcase-2024-dev/lib/python3.10/site-packages/pyart/io/cfradial.py:412: UserWarning: WARNING: valid_max not used since it
cannot be safely cast to variable data type
  data = self.ncvar[:]

<pyart.core.radar.Radar at 0x7f1d57106dd0>

Create a Quick Plot

One of Py-ART’s key benefits is the easy plotting classes users can utilize with their radar object!

More plotting examples in the gallery

display = pyart.graph.RadarDisplay(radar)
display.plot("corrected_reflectivity")

Ivestigate the radar object

But… how did we know that field was in there? What the heck is this object?

dir(radar)

['__class__',
 '__delattr__',
 '__dict__',
 '__dir__',
 '__doc__',
 '__eq__',
 '__format__',
 '__ge__',
 '__getattribute__',
 '__getstate__',
 '__gt__',
 '__hash__',
 '__init__',
 '__init_subclass__',
 '__le__',
 '__lt__',
 '__module__',
 '__ne__',
 '__new__',
 '__reduce__',
 '__reduce_ex__',
 '__repr__',
 '__setattr__',
 '__setstate__',
 '__sizeof__',
 '__str__',
 '__subclasshook__',
 '__weakref__',
 '_check_sweep_in_range',
 '_dic_info',
 'add_field',
 'add_field_like',
 'add_filter',
 'altitude',
 'altitude_agl',
 'antenna_transition',
 'azimuth',
 'check_field_exists',
 'drift',
 'elevation',
 'extract_sweeps',
 'fields',
 'fixed_angle',
 'gate_altitude',
 'gate_latitude',
 'gate_longitude',
 'gate_x',
 'gate_y',
 'gate_z',
 'georefs_applied',
 'get_azimuth',
 'get_elevation',
 'get_end',
 'get_field',
 'get_gate_area',
 'get_gate_lat_lon_alt',
 'get_gate_x_y_z',
 'get_nyquist_vel',
 'get_slice',
 'get_start',
 'get_start_end',
 'heading',
 'info',
 'init_gate_altitude',
 'init_gate_longitude_latitude',
 'init_gate_x_y_z',
 'init_rays_per_sweep',
 'instrument_parameters',
 'iter_azimuth',
 'iter_elevation',
 'iter_end',
 'iter_field',
 'iter_slice',
 'iter_start',
 'iter_start_end',
 'latitude',
 'longitude',
 'metadata',
 'ngates',
 'nrays',
 'nsweeps',
 'pitch',
 'projection',
 'radar_calibration',
 'range',
 'ray_angle_res',
 'rays_are_indexed',
 'rays_per_sweep',
 'roll',
 'rotation',
 'scan_rate',
 'scan_type',
 'sweep_end_ray_index',
 'sweep_mode',
 'sweep_number',
 'sweep_start_ray_index',
 'target_scan_rate',
 'tilt',
 'time']

Where’s the data???

It’s all in the fields!

A dictionary of dictionaries… ahhh pre-xarray days…

radar.fields

{'DBZ': {'_FillValue': -32768.0,
  'long_name': 'Equaivalent_radar_reflectiivity_factor',
  'units': 'dBZ',
  'standard_name': 'equivalent_reflectivity_factor',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[ 5.3499999 ,  9.38999939,  9.60999966, ...,  7.50999975,
            3.56999993,  7.52999973],
          [ 6.85999966,  8.85999966,  8.43999958, ...,  7.50999975,
            4.9000001 ,  7.52999973],
          [ 7.26999998,  8.97999954,  4.21999979, ...,  7.50999975,
            4.9000001 ,  7.52999973],
          ...,
          [10.11999989,  8.34999943,  8.13999939, ...,  7.50999975,
            7.51999998,  7.52999973],
          [ 8.94999981,  6.36999989,  6.96000004, ...,  7.50999975,
            7.51999998,  7.52999973],
          [ 7.61999989,  6.30999994,  5.29999971, ...,  7.50999975,
            7.51999998,  7.52999973]],
    mask=False,
    fill_value=1e+20)},
 'VEL': {'_FillValue': -32768.0,
  'long_name': 'Radial Doppler Velocity, Positive for Motion Away from Instrument',
  'units': 'm/s',
  'standard_name': 'radial_velocity_of_scatterers_away_from_instruments',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[  1.76999998,   2.76999998,   3.74000001, ...,  -6.37999964,
            -1.14999998,  -3.05999994],
          [  1.96999991,   2.54999995,   3.7099998 , ...,  -5.19999981,
            -3.05999994,  -5.31999969],
          [  1.82999992,   2.78999996,   3.68999982, ...,  -8.92999935,
            -3.88999987,  13.27999973],
          ...,
          [  1.5999999 ,   1.41999996,   2.08999991, ...,   3.52999997,
            27.40999985,  23.70999908],
          [  1.56999993,   1.14999998,   2.        , ...,   3.80999994,
            -3.24000001,  23.        ],
          [  1.5999999 ,   1.30999994,   2.11999989, ...,   3.27999997,
           -24.88999939,   0.38999999]],
    mask=False,
    fill_value=1e+20)},
 'WIDTH': {'_FillValue': -32768.0,
  'long_name': 'Spectral Width',
  'units': 'm/s',
  'standard_name': 'doppler_spectrum_width',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[1.69999993, 2.46000004, 1.17999995, ..., 3.30999994, 3.02999997,
           2.12999988],
          [1.75      , 2.26999998, 0.98999995, ..., 2.95000005, 3.63999987,
           2.50999999],
          [1.71999991, 2.19000006, 1.41999996, ..., 2.32999992, 3.77999997,
           2.71000004],
          ...,
          [1.01999998, 1.01999998, 0.63      , ..., 2.96000004, 3.01999998,
           2.20000005],
          [1.09000003, 1.18999994, 0.68000001, ..., 2.96000004, 2.78999996,
           1.89999998],
          [1.33999991, 1.25      , 0.88999999, ..., 2.25999999, 2.63999987,
           2.91999984]],
    mask=False,
    fill_value=1e+20)},
 'ZDR': {'_FillValue': -32768.0,
  'long_name': 'Differential Reflectivity',
  'units': 'dB',
  'standard_name': 'log_differential_reflectivity_hv',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[1.85000007, 3.53999998, 2.97      , ..., 1.82999997, 3.60000001,
           2.13000004],
          [2.27000003, 3.80999999, 2.67      , ..., 2.32000004, 2.32000004,
           2.56000002],
          [2.71      , 3.84999995, 3.19999999, ..., 2.67      , 2.00000005,
           2.54000001],
          ...,
          [3.09      , 3.94999998, 3.02      , ..., 3.03      , 3.55999999,
           2.54000001],
          [3.49999999, 4.03999995, 2.98      , ..., 3.31999998, 2.36999999,
           2.34000002],
          [3.76999997, 3.57999997, 3.62999998, ..., 3.66000001, 2.15000002,
           2.68      ]],
    mask=False,
    fill_value=1e+20)},
 'PHIDP': {'_FillValue': -32768.0,
  'long_name': 'Differential Phase',
  'units': 'degree',
  'standard_name': 'differential_phase_hv',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[ 89.95999908,  96.76999664,  98.90000153, ..., 280.95999908,
           299.26000214, 293.23000336],
          [ 94.04999542,  98.37999725,  99.62999725, ..., 282.26000214,
           350.5       , 248.79000092],
          [ 93.45999908, 100.20999908,  97.38999939, ..., 321.63999939,
           329.46000099, 303.17000198],
          ...,
          [ 98.29999542, 104.27999878, 102.98999786, ...,  59.59000015,
           334.52000046, 333.11000061],
          [ 98.63999939, 104.90999603, 101.22000122, ...,  27.56999969,
           327.94000244, 315.49000168],
          [ 99.16999817, 105.11999512, 106.        , ..., 319.04999924,
           349.60000038, 338.90999985]],
    mask=False,
    fill_value=1e+20)},
 'RHOHV': {'_FillValue': -32768.0,
  'long_name': 'Cross-Polar Correlation Ratio',
  'units': '1',
  'standard_name': 'cross_correlation_ratio_hv',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[0.97400004, 0.99200004, 0.99300003, ..., 0.70700002, 0.33100003,
           0.46600002],
          [0.96700007, 0.98200005, 0.98300004, ..., 0.81400001, 0.37300003,
           0.45500001],
          [0.95600003, 0.97800004, 0.96200007, ..., 0.53800005, 0.62200004,
           0.44500002],
          ...,
          [0.98000002, 0.98100007, 0.98200005, ..., 0.33600003, 0.38500002,
           0.71100003],
          [0.97000003, 0.97700006, 0.98300004, ..., 0.38200003, 0.45300001,
           0.56700003],
          [0.96000004, 0.98000002, 0.97500002, ..., 0.42800003, 0.54500002,
           0.34800002]],
    mask=False,
    fill_value=1e+20)},
 'NCP': {'_FillValue': -32768.0,
  'long_name': 'Normalized Coherent Power, also known as SQI',
  'units': '1',
  'standard_name': 'normalized_coherent_power',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[0.90999997, 0.83999997, 0.91999996, ..., 0.16      , 0.14      ,
           0.17      ],
          [0.90999997, 0.85999995, 0.94999999, ..., 0.11      , 0.14      ,
           0.22      ],
          [0.89999998, 0.87      , 0.93000001, ..., 0.12      , 0.14      ,
           0.22      ],
          ...,
          [0.95999998, 0.95999998, 0.97999996, ..., 0.11      , 0.17999999,
           0.13      ],
          [0.95999998, 0.94      , 0.96999997, ..., 0.09999999, 0.14999999,
           0.14999999],
          [0.94999999, 0.93000001, 0.95999998, ..., 0.09999999, 0.11      ,
           0.13      ]],
    mask=False,
    fill_value=1e+20)},
 'DBZhv': {'_FillValue': -32768.0,
  'long_name': 'Equivalent Reflectivity Factor HV',
  'units': 'dBZ',
  'standard_name': 'equivalent_reflectivity_factor_hv',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[ 6.39999962,  9.17000008,  9.55000019, ..., -0.76999998,
           -1.81999993, -1.31999993],
          [ 7.75999975,  7.86999989,  7.90999985, ..., -0.53999996,
           -1.65999997, -1.52999997],
          [ 7.46999979,  7.94999981,  2.42999983, ..., -0.22      ,
            0.25999999, -1.25999999],
          ...,
          [11.13999939,  9.40999985,  8.71000004, ..., -1.32999992,
           -1.16999996, -2.3499999 ],
          [ 9.28999996,  5.44999981,  7.51999998, ..., -0.57999998,
           -0.44999999, -6.        ],
          [ 7.46000004,  4.26999998,  3.07999992, ..., -1.63      ,
           -0.82999998, -3.02999997]],
    mask=False,
    fill_value=1e+20)},
 'cbb_flag': {'long_name': 'Cumulative Beam Block Fraction Flag',
  'units': '1',
  'coordinates': 'elevation azimuth range',
  'comment': 'Cumulative beam block flag due to terrain.',
  'data': masked_array(
    data=[[0., 0., 0., ..., 1., 1., 1.],
          [0., 0., 0., ..., 1., 1., 1.],
          [0., 0., 0., ..., 1., 1., 1.],
          ...,
          [0., 0., 0., ..., 0., 0., 0.],
          [0., 0., 0., ..., 0., 0., 0.],
          [0., 0., 0., ..., 0., 0., 0.]],
    mask=False,
    fill_value=1e+20)},
 'sounding_temperature': {'long_name': 'Interpolated profile',
  'units': 'degC',
  'standard_name': 'interpolated_profile',
  'data': masked_array(
    data=[[ -2.3462055,  -2.4152544,  -2.4588518, ..., -34.118    ,
           -34.18     , -34.232002 ],
          [ -2.3462055,  -2.4152544,  -2.4588518, ..., -34.15     ,
           -34.208    , -34.258    ],
          [ -2.3462055,  -2.4152544,  -2.468688 , ..., -34.190002 ,
           -34.24     , -34.278    ],
          ...,
          [ -2.3565507,  -2.4152544,  -2.468688 , ..., -34.381226 ,
           -34.42917  , -34.471428 ],
          [ -2.3565507,  -2.4152544,  -2.468688 , ..., -34.381226 ,
           -34.42917  , -34.471428 ],
          [ -2.3565507,  -2.4152544,  -2.468688 , ..., -34.381226 ,
           -34.42917  , -34.471428 ]],
    mask=False,
    fill_value=1e+20,
    dtype=float32)},
 'height': {'long_name': 'Height of radar beam',
  'units': 'm',
  'standard_name': 'height',
  'data': masked_array(
    data=[[3180.2, 3187.2, 3192.2, ..., 7398.2, 7405.2, 7411.2],
          [3180.2, 3187.2, 3192.2, ..., 7402.2, 7408.2, 7415.2],
          [3180.2, 3187.2, 3193.2, ..., 7406.2, 7412.2, 7418.2],
          ...,
          [3181.2, 3187.2, 3193.2, ..., 7432.2, 7439.2, 7445.2],
          [3181.2, 3187.2, 3193.2, ..., 7432.2, 7439.2, 7445.2],
          [3181.2, 3187.2, 3193.2, ..., 7432.2, 7439.2, 7445.2]],
    mask=False,
    fill_value=1e+20,
    dtype=float32)},
 'signal_to_noise_ratio': {'_FillValue': -32768.0,
  'long_name': 'Signal to Noise Ratio',
  'units': 'dB',
  'standard_name': 'signal_to_noise_ratio',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[40.18000031, 42.66999817, 41.56999969, ...,  0.        ,
           -3.94999981,  0.        ],
          [41.68999863, 42.13999939, 40.39999771, ...,  0.        ,
           -2.61999989,  0.        ],
          [42.09000015, 42.25      , 36.18000031, ...,  0.        ,
           -2.61999989,  0.        ],
          ...,
          [44.95000076, 41.62999725, 40.11000061, ...,  0.        ,
            0.        ,  0.        ],
          [43.77999878, 39.63999939, 38.91999817, ...,  0.        ,
            0.        ,  0.        ],
          [42.45000076, 39.59000015, 37.25999832, ...,  0.        ,
            0.        ,  0.        ]],
    mask=False,
    fill_value=1e+20)},
 'velocity_texture': {'long_name': 'Mean dopper velocity',
  'units': 'm/s',
  'standard_name': 'radial_velocity_of_scatterers_away_from_instrument',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[0.95980847, 0.88251601, 0.83554892, ..., 6.45901397, 5.62455843,
           5.00792857],
          [0.83920148, 0.83554892, 0.79410012, ..., 6.41084159, 5.62455843,
           5.00792857],
          [0.79410012, 0.73037925, 0.73037925, ..., 6.30690828, 6.02653167,
           5.34782884],
          ...,
          [0.29748918, 0.30600555, 0.45446138, ..., 5.26087378, 5.38360144,
           5.38360144],
          [0.29443759, 0.29443759, 0.45446138, ..., 4.9112846 , 5.22778187,
           5.52338061],
          [0.28717293, 0.28717293, 0.46040409, ..., 4.52095116, 5.10617287,
           5.22778187]],
    mask=False,
    fill_value=1e+20)},
 'gate_id': {'long_name': 'Classification of dominant scatterer',
  'units': '1',
  'notes': '0:multi_trip,1:rain,2:snow,3:no_scatter,4:melting,5:clutter,6:terrain_blockage',
  'valid_max': '6',
  'valid_min': '0',
  'flag_values': '0, 1, 2, 3, 4, 5, 6',
  'flag_meanings': 'multi_trip rain snow no_scatter melting clutter terrain_blockage',
  'data': masked_array(
    data=[[2, 2, 2, ..., 6, 6, 6],
          [2, 2, 2, ..., 6, 6, 6],
          [2, 2, 2, ..., 6, 6, 6],
          ...,
          [2, 2, 2, ..., 3, 3, 3],
          [2, 2, 2, ..., 3, 3, 3],
          [2, 2, 2, ..., 3, 3, 3]],
    mask=False,
    fill_value=999999)},
 'simulated_velocity': {'long_name': 'Simulated mean doppler velocity',
  'units': 'm/s',
  'standard_name': 'radial_velocity_of_scatterers_away_from_instrument',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[-4.04460068, -3.96199123, -3.94839799, ..., 12.92917905,
           12.92917905, 12.96911246],
          [-4.04456044, -3.96195182, -3.94835871, ..., 12.92905043,
           12.93903185, 12.97896974],
          [-4.03869838, -3.95620948, -3.92755288, ..., 13.0073836 ,
           13.05760291, 13.05760536],
          ...,
          [-4.02602798, -3.9593496 , -3.93067025, ..., 12.95954531,
           12.95954531, 12.95954531],
          [-4.02602798, -3.9593496 , -3.93067025, ..., 12.95954531,
           12.95954531, 12.95954531],
          [-4.02602798, -3.9593496 , -3.93067025, ..., 12.95954531,
           12.95954531, 12.95954531]],
    mask=False,
    fill_value=1e+20)},
 'corrected_velocity': {'_FillValue': -32768.0,
  'long_name': 'Corrected mean doppler velocity',
  'units': 'm/s',
  'standard_name': 'corrected_radial_velocity_of_scatterers_away_from_instrument',
  'coordinates': 'elevation azimuth range',
  'valid_min': '-79.5',
  'valid_max': '79.5',
  'data': masked_array(
    data=[[1.7699999809265137, 2.7699999809265137, 3.740000009536743, ...,
           --, --, --],
          [1.96999990940094, 2.549999952316284, 3.7099997997283936, ...,
           --, --, --],
          [1.8299999237060547, 2.7899999618530273, 3.68999981880188, ...,
           --, --, --],
          ...,
          [1.5999999046325684, 1.4199999570846558, 2.0899999141693115, ...,
           --, --, --],
          [1.5699999332427979, 1.149999976158142, 2.0, ..., --, --, --],
          [1.5999999046325684, 1.309999942779541, 2.119999885559082, ...,
           --, --, --]],
    mask=[[False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          ...,
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True]],
    fill_value=-32768.0)},
 'unfolded_differential_phase': {'_FillValue': -32768.0,
  'long_name': 'Unfolded differential propagation phase shift',
  'units': 'degree',
  'standard_name': 'differential_phase_hv',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[0., 0., 0., ..., 0., 0., 0.],
          [0., 0., 0., ..., 0., 0., 0.],
          [0., 0., 0., ..., 0., 0., 0.],
          ...,
          [0., 0., 0., ..., 0., 0., 0.],
          [0., 0., 0., ..., 0., 0., 0.],
          [0., 0., 0., ..., 0., 0., 0.]],
    mask=False,
    fill_value=1e+20)},
 'corrected_differential_phase': {'_FillValue': -32768.0,
  'long_name': 'Corrected differential propagation phase shift',
  'units': 'degree',
  'standard_name': 'differential_phase_hv',
  'coordinates': 'elevation azimuth range',
  'valid_min': '0.0',
  'valid_max': '400.0',
  'data': masked_array(
    data=[[0.01, 0.01, 0.01, ..., 0.01, 0.01, 0.01],
          [0.01, 0.01, 0.01, ..., 0.01, 0.01, 0.01],
          [0.01, 0.01, 0.01, ..., 0.01, 0.01, 0.01],
          ...,
          [0.01, 0.01, 0.01, ..., 0.01, 0.01, 0.01],
          [0.01, 0.01, 0.01, ..., 0.01, 0.01, 0.01],
          [0.01, 0.01, 0.01, ..., 0.01, 0.01, 0.01]],
    mask=False,
    fill_value=1e+20)},
 'filtered_corrected_differential_phase': {'_FillValue': -32768.0,
  'long_name': 'Filtered Corrected Differential Phase',
  'units': 'degree',
  'standard_name': 'differential_phase_hv',
  'coordinates': 'elevation azimuth range',
  'valid_min': '0.0',
  'valid_max': '400.0',
  'data': masked_array(
    data=[[-4.36452341e-21, -1.30935702e-20, -2.61871405e-20, ...,
           -6.05577610e-19, -6.05577610e-19,  1.00000000e-02],
          [-4.36452341e-21, -1.30935702e-20, -2.61871405e-20, ...,
           -5.55749303e-19, -5.55749303e-19,  1.00000000e-02],
          [-4.36452341e-21, -1.30935702e-20, -2.61871405e-20, ...,
           -4.88462899e-19, -4.88462899e-19,  1.00000000e-02],
          ...,
          [-4.36452341e-21, -1.30935702e-20, -2.61871405e-20, ...,
           -5.34654088e-19, -5.34654088e-19,  1.00000000e-02],
          [-4.36452341e-21, -1.30935702e-20, -2.61871405e-20, ...,
           -6.41221224e-19, -6.41221224e-19,  1.00000000e-02],
          [-4.36452341e-21, -1.30935702e-20, -2.61871405e-20, ...,
           -6.41221224e-19, -6.41221224e-19,  1.00000000e-02]],
    mask=False,
    fill_value=1e+20)},
 'corrected_specific_diff_phase': {'_FillValue': -9999.0,
  'long_name': 'Specific differential phase (KDP)',
  'units': 'degrees/km',
  'standard_name': 'specific_differential_phase_hv',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[-2.43197823e-20, -7.29593470e-20, -1.21598912e-19, ...,
            0.00000000e+00,  0.00000000e+00,  0.00000000e+00],
          [-2.43197823e-20, -7.29593470e-20, -1.21598912e-19, ...,
            0.00000000e+00,  0.00000000e+00,  0.00000000e+00],
          [-2.43197823e-20, -7.29593470e-20, -1.21598912e-19, ...,
            0.00000000e+00,  0.00000000e+00,  0.00000000e+00],
          ...,
          [-2.43197823e-20, -7.29593470e-20, -1.21598912e-19, ...,
            0.00000000e+00,  0.00000000e+00,  0.00000000e+00],
          [-2.43197823e-20, -7.29593470e-20, -1.21598912e-19, ...,
            0.00000000e+00,  0.00000000e+00,  0.00000000e+00],
          [-2.43197823e-20, -7.29593470e-20, -1.21598912e-19, ...,
            0.00000000e+00,  0.00000000e+00,  0.00000000e+00]],
    mask=False,
    fill_value=1e+20)},
 'filtered_corrected_specific_diff_phase': {'_FillValue': -9999.0,
  'long_name': 'Filtered Corrected Specific differential phase (KDP)',
  'units': 'degrees/km',
  'standard_name': 'specific_differential_phase_hv',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[-2.43197823e-20, -7.29593470e-20, -1.21598912e-19, ...,
            0.00000000e+00,  0.00000000e+00,  0.00000000e+00],
          [-2.43197823e-20, -7.29593470e-20, -1.21598912e-19, ...,
            0.00000000e+00,  0.00000000e+00,  0.00000000e+00],
          [-2.43197823e-20, -7.29593470e-20, -1.21598912e-19, ...,
            0.00000000e+00,  0.00000000e+00,  0.00000000e+00],
          ...,
          [-2.43197823e-20, -7.29593470e-20, -1.21598912e-19, ...,
            0.00000000e+00,  0.00000000e+00,  0.00000000e+00],
          [-2.43197823e-20, -7.29593470e-20, -1.21598912e-19, ...,
            0.00000000e+00,  0.00000000e+00,  0.00000000e+00],
          [-2.43197823e-20, -7.29593470e-20, -1.21598912e-19, ...,
            0.00000000e+00,  0.00000000e+00,  0.00000000e+00]],
    mask=False,
    fill_value=1e+20)},
 'corrected_differential_reflectivity': {'_FillValue': 1e+20,
  'long_name': 'Corrected differential reflectivity',
  'units': 'dB',
  'standard_name': 'corrected_log_differential_reflectivity_hv',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[1.8500000715255736, 3.5399999797344206, 2.970000001788139, ...,
           --, --, --],
          [2.2700000286102293, 3.8099999904632567, 2.6700000047683714, ...,
           --, --, --],
          [2.709999996423721, 3.849999952316284, 3.199999991059303, ...,
           --, --, --],
          ...,
          [3.08999999910593, 3.949999976158142, 3.020000000670552, ..., --,
           --, --],
          [3.499999988079071, 4.039999949932098, 2.9799999997019766, ...,
           --, --, --],
          [3.7699999690055845, 3.5799999713897703, 3.6299999833106993, ...,
           --, --, --]],
    mask=[[False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          ...,
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True]],
    fill_value=1e+20)},
 'corrected_reflectivity': {'_FillValue': 1e+20,
  'long_name': 'Corrected reflectivity',
  'units': 'dBZ',
  'standard_name': 'corrected_equivalent_reflectivity_factor',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[5.349999904632568, 9.389999389648438, 9.609999656677246, ...,
           --, --, --],
          [6.859999656677246, 8.859999656677246, 8.4399995803833, ..., --,
           --, --],
          [7.269999980926514, 8.979999542236328, 4.21999979019165, ..., --,
           --, --],
          ...,
          [10.119999885559082, 8.34999942779541, 8.139999389648438, ...,
           --, --, --],
          [8.949999809265137, 6.369999885559082, 6.960000038146973, ...,
           --, --, --],
          [7.619999885559082, 6.309999942779541, 5.299999713897705, ...,
           --, --, --]],
    mask=[[False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          ...,
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True]],
    fill_value=1e+20)},
 'height_over_iso0': {'long_name': 'Height of radar beam over freezing level',
  'units': 'm',
  'standard_name': 'height',
  'data': masked_array(
    data=[[nan, nan, nan, ..., nan, nan, nan],
          [nan, nan, nan, ..., nan, nan, nan],
          [nan, nan, nan, ..., nan, nan, nan],
          ...,
          [nan, nan, nan, ..., nan, nan, nan],
          [nan, nan, nan, ..., nan, nan, nan],
          [nan, nan, nan, ..., nan, nan, nan]],
    mask=False,
    fill_value=1e+20,
    dtype=float32)},
 'specific_attenuation': {'_FillValue': 1e+20,
  'long_name': 'Specific attenuation',
  'units': 'dB/km',
  'standard_name': 'specific_attenuation',
  'coordinates': 'elevation azimuth range',
  'valid_min': '0.0',
  'valid_max': '1.0',
  'data': masked_array(
    data=[[0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          ...,
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --]],
    mask=[[False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          ...,
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True]],
    fill_value=1e+20)},
 'path_integrated_attenuation': {'_FillValue': 1e+20,
  'long_name': 'Path Integrated Attenuation',
  'units': 'dB',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          ...,
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --]],
    mask=[[False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          ...,
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True]],
    fill_value=1e+20)},
 'specific_differential_attenuation': {'_FillValue': 1e+20,
  'long_name': 'Specific Differential Attenuation',
  'units': 'dB/km',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          ...,
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --]],
    mask=[[False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          ...,
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True]],
    fill_value=1e+20)},
 'path_integrated_differential_attenuation': {'_FillValue': 1e+20,
  'long_name': 'Path Integrated Differential Attenuation',
  'units': 'dB',
  'coordinates': 'elevation azimuth range',
  'data': masked_array(
    data=[[0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          ...,
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --]],
    mask=[[False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          ...,
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True]],
    fill_value=1e+20)},
 'rain_rate_A': {'_FillValue': 1e+20,
  'long_name': 'Rainfall Rate from Specific Attenuation',
  'units': 'mm/hr',
  'standard_name': 'rainfall_rate',
  'coordinates': 'elevation azimuth range',
  'least_significant_digit': 1,
  'comment': 'Rain rate calculated from specific_attenuation, R=43.5*specific_attenuation**0.79, note R=0.0 where norm coherent power < 0.4 or rhohv < 0.8',
  'valid_min': '0.0',
  'valid_max': '400.0',
  'data': masked_array(
    data=[[0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          ...,
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --],
          [0.0, 0.0, 0.0, ..., --, --, --]],
    mask=[[False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          ...,
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True]],
    fill_value=1e+20)},
 'snow_rate_ws2012': {'_FillValue': 1e+20,
  'long_name': 'Snowfall rate from Z using Wolf and Snider (2012)',
  'units': 'mm/h',
  'standard_name': 'snowfall_rate',
  'coordinates': 'elevation azimuth range',
  'valid_min': '0',
  'valid_max': '500',
  'swe_ratio': '13.699',
  'A': '110',
  'B': '2',
  'data': masked_array(
    data=[[0.17652395640137936, 0.28106296725172597, 0.28827278262198935,
           ..., --, --, --],
          [0.2100407886358824, 0.2644256863269999, 0.25194377738869717,
           ..., --, --, --],
          [0.22019307501812282, 0.2681042105157746, 0.1549899888164853,
           ..., --, --, --],
          ...,
          [0.3057057811683439, 0.2493467022536862, 0.24339050225771308,
           ..., --, --, --],
          [0.267179816896248, 0.19851971895737944, 0.21247295567206081,
           ..., --, --, --],
          [0.22924699505759605, 0.19715312012338218, 0.1755107180920355,
           ..., --, --, --]],
    mask=[[False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          ...,
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True]],
    fill_value=1e+20)},
 'snow_rate_ws88diw': {'_FillValue': 1e+20,
  'long_name': 'Snowfall rate from Z using WSR 88D High Plains',
  'units': 'mm/h',
  'standard_name': 'snowfall_rate',
  'coordinates': 'elevation azimuth range',
  'valid_min': '0',
  'valid_max': '500',
  'swe_ratio': '13.699',
  'A': '40',
  'B': '2',
  'data': masked_array(
    data=[[0.2927318649462153, 0.46609020241896115, 0.47804632861441165,
           ..., --, --, --],
          [0.3483132432877832, 0.4385003932394344, 0.4178014889315676, ...,
           --, --, --],
          [0.36514890563484625, 0.44460053549764045, 0.2570218195828306,
           ..., --, --, --],
          ...,
          [0.5069556861889462, 0.4134947270439711, 0.4036174867624916, ...,
           --, --, --],
          [0.4430676021003563, 0.3292077106342157, 0.35234653603102045,
           ..., --, --, --],
          [0.3801631334612524, 0.3269414628485627, 0.29105159929856145,
           ..., --, --, --]],
    mask=[[False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          ...,
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True]],
    fill_value=1e+20)},
 'snow_rate_m2009_1': {'_FillValue': 1e+20,
  'long_name': 'Snowfall rate from Z using Matrosov et al.(2009) Braham(1990) 1',
  'units': 'mm/h',
  'standard_name': 'snowfall_rate',
  'coordinates': 'elevation azimuth range',
  'valid_min': '0',
  'valid_max': '500',
  'swe_ratio': '13.699',
  'A': '67',
  'B': '1.28',
  'data': masked_array(
    data=[[0.09802747200957339, 0.2027555554981298, 0.21094065176843244,
           ..., --, --, --],
          [0.1286223776774802, 0.18431748402559525, 0.17090470838886448,
           ..., --, --, --],
          [0.13846748651837235, 0.1883395483532741, 0.07999568175760745,
           ..., --, --, --],
          ...,
          [0.23120863590817595, 0.16816002594348523, 0.1619259720053442,
           ..., --, --, --],
          [0.18732588605183864, 0.11777016986310176, 0.130957104270401,
           ..., --, --, --],
          [0.14746588157528065, 0.116505869632889, 0.09714971660031632,
           ..., --, --, --]],
    mask=[[False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          ...,
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True]],
    fill_value=1e+20)},
 'snow_rate_m2009_2': {'_FillValue': 1e+20,
  'long_name': 'Snowfall rate from Z using Matrosov et al.(2009) Braham(1990) 2',
  'units': 'mm/h',
  'standard_name': 'snowfall_rate',
  'coordinates': 'elevation azimuth range',
  'valid_min': '0',
  'valid_max': '500',
  'swe_ratio': '13.699',
  'A': '114',
  'B': '1.39',
  'data': masked_array(
    data=[[0.08037193357461173, 0.1569465818472422, 0.16277181979683336,
           ..., --, --, --],
          [0.10321373456165439, 0.14375480980848285, 0.13409313722293925,
           ..., --, --, --],
          [0.11046734559487273, 0.1466410189496867, 0.06665142582252989,
           ..., --, --, --],
          ...,
          [0.17712092960144296, 0.13210879171494475, 0.12759210547463656,
           ..., --, --, --],
          [0.14591408480746687, 0.09516685344560759, 0.10493775392442406,
           ..., --, --, --],
          [0.11706141455918391, 0.09422565554197429, 0.0797089853078306,
           ..., --, --, --]],
    mask=[[False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          ...,
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True],
          [False, False, False, ...,  True,  True,  True]],
    fill_value=1e+20)}}

Introduction to xradar

Re-writing the readers, coming to a community standard.

Reading data using xradar

We can read in a single elevation (ex. sweep_0)

first_sweep = xr.open_dataset(file, engine='cfradial1', group='sweep_0')
first_sweep

<xarray.Dataset> Size: 195MB
Dimensions:                                   (azimuth: 1159, range: 668)
Coordinates:
    time                                      (azimuth) datetime64[ns] 9kB ...
  * range                                     (range) float32 3kB 306.9 ... 4...
    elevation                                 (azimuth) float32 5kB ...
  * azimuth                                   (azimuth) float32 5kB 0.05238 ....
    latitude                                  float64 8B ...
    longitude                                 float64 8B ...
    altitude                                  float64 8B ...
Data variables: (12/37)
    DBZ                                       (azimuth, range) float64 6MB ...
    VEL                                       (azimuth, range) float64 6MB ...
    WIDTH                                     (azimuth, range) float64 6MB ...
    ZDR                                       (azimuth, range) float64 6MB ...
    PHIDP                                     (azimuth, range) float64 6MB ...
    RHOHV                                     (azimuth, range) float64 6MB ...
    ...                                        ...
    snow_rate_m2009_1                         (azimuth, range) float64 6MB ...
    snow_rate_m2009_2                         (azimuth, range) float64 6MB ...
    sweep_number                              int32 4B ...
    sweep_fixed_angle                         float32 4B ...
    sweep_mode                                <U188 752B ...
    nyquist_velocity                          (azimuth) float64 9kB ...

xarray.Dataset

• Dimensions:
  • azimuth: 1159
  • range: 668
• Coordinates: (7)
  • time
    (azimuth)
    datetime64[ns]
    ...

    long_name :

    Time in Seconds from Volume Start

    standard_name :

    time

    [1159 values with dtype=datetime64[ns]]

  • range
    (range)
    float32
    306.9 366.8 ... 4.023e+04 4.029e+04

    long_name :

    Range to measurement volume

    units :

    meter

    standard_name :

    projection_range_coordinate

    spacing_is_constant :

    true

    axis :

    radial_range_coordinate

    meters_to_center_of_first_gate :

    -112.6891

    meters_between_gates :

    59.94095

    array([  306.88168,   366.82263,   426.76358, ..., 40167.61   , 40227.555  ,
           40287.496  ], dtype=float32)

  • elevation
    (azimuth)
    float32
    ...

    long_name :

    Elevation angle from horizontal plane

    units :

    degree

    axis :

    radial_elevation_coordinate

    standard_name :

    sensor_to_target_elevation_angle

    [1159 values with dtype=float32]

  • azimuth
    (azimuth)
    float32
    0.05238 0.1128 ... 359.9 360.0

    long_name :

    Azimuth Angle from True North

    units :

    degree

    axis :

    radial_azimuth_coordinate

    standard_name :

    sensor_to_target_azimuth_angle

    array([5.238281e-02, 1.128076e-01, 1.250684e-01, ..., 3.597612e+02,
           3.598821e+02, 3.599755e+02], dtype=float32)

  • latitude
    ()
    float64
    ...

    long_name :

    Latitude

    units :

    degree_N

    standard_name :

    latitude

    valid_min :

    -90.0

    valid_max :

    90.0

    [1 values with dtype=float64]

  • longitude
    ()
    float64
    ...

    long_name :

    Longitude

    units :

    degree_E

    standard_name :

    longitude

    valid_min :

    -180.0

    valid_max :

    180.0

    [1 values with dtype=float64]

  • altitude
    ()
    float64
    ...

    long_name :

    Altitude

    units :

    m

    standard_name :

    altitude

    [1 values with dtype=float64]

• Data variables: (37)
  • DBZ
    (azimuth, range)
    float64
    ...

    long_name :

    Equaivalent_radar_reflectiivity_factor

    units :

    dBZ

    standard_name :

    equivalent_reflectivity_factor

    [774212 values with dtype=float64]

  • VEL
    (azimuth, range)
    float64
    ...

    long_name :

    Radial Doppler Velocity, Positive for Motion Away from Instrument

    units :

    m/s

    standard_name :

    radial_velocity_of_scatterers_away_from_instruments

    [774212 values with dtype=float64]

  • WIDTH
    (azimuth, range)
    float64
    ...

    long_name :

    Spectral Width

    units :

    m/s

    standard_name :

    doppler_spectrum_width

    [774212 values with dtype=float64]

  • ZDR
    (azimuth, range)
    float64
    ...

    long_name :

    Differential Reflectivity

    units :

    dB

    standard_name :

    log_differential_reflectivity_hv

    [774212 values with dtype=float64]

  • PHIDP
    (azimuth, range)
    float64
    ...

    long_name :

    Differential Phase

    units :

    degree

    standard_name :

    differential_phase_hv

    [774212 values with dtype=float64]

  • RHOHV
    (azimuth, range)
    float64
    ...

    long_name :

    Cross-Polar Correlation Ratio

    units :

    1

    standard_name :

    cross_correlation_ratio_hv

    [774212 values with dtype=float64]

  • NCP
    (azimuth, range)
    float64
    ...

    long_name :

    Normalized Coherent Power, also known as SQI

    units :

    1

    standard_name :

    normalized_coherent_power

    [774212 values with dtype=float64]

  • DBZhv
    (azimuth, range)
    float64
    ...

    long_name :

    Equivalent Reflectivity Factor HV

    units :

    dBZ

    standard_name :

    equivalent_reflectivity_factor_hv

    [774212 values with dtype=float64]

  • cbb_flag
    (azimuth, range)
    float64
    ...

    long_name :

    Cumulative Beam Block Fraction Flag

    units :

    1

    comment :

    Cumulative beam block flag due to terrain.

    [774212 values with dtype=float64]

  • sounding_temperature
    (azimuth, range)
    float32
    ...

    long_name :

    Interpolated profile

    units :

    degC

    standard_name :

    interpolated_profile

    [774212 values with dtype=float32]

  • height
    (azimuth, range)
    float32
    ...

    long_name :

    Height of radar beam

    units :

    m

    standard_name :

    height

    [774212 values with dtype=float32]

  • signal_to_noise_ratio
    (azimuth, range)
    float64
    ...

    long_name :

    Signal to Noise Ratio

    units :

    dB

    standard_name :

    signal_to_noise_ratio

    [774212 values with dtype=float64]

  • velocity_texture
    (azimuth, range)
    float64
    ...

    long_name :

    Mean dopper velocity

    units :

    m/s

    standard_name :

    radial_velocity_of_scatterers_away_from_instrument

    [774212 values with dtype=float64]

  • gate_id
    (azimuth, range)
    int64
    ...

    long_name :

    Classification of dominant scatterer

    units :

    1

    notes :

    0:multi_trip,1:rain,2:snow,3:no_scatter,4:melting,5:clutter,6:terrain_blockage

    valid_max :

    6

    valid_min :

    0

    flag_values :

    0, 1, 2, 3, 4, 5, 6

    flag_meanings :

    multi_trip rain snow no_scatter melting clutter terrain_blockage

    [774212 values with dtype=int64]

  • simulated_velocity
    (azimuth, range)
    float64
    ...

    long_name :

    Simulated mean doppler velocity

    units :

    m/s

    standard_name :

    radial_velocity_of_scatterers_away_from_instrument

    [774212 values with dtype=float64]

  • corrected_velocity
    (azimuth, range)
    float64
    ...

    long_name :

    Corrected mean doppler velocity

    units :

    m/s

    standard_name :

    corrected_radial_velocity_of_scatterers_away_from_instrument

    valid_min :

    -79.5

    valid_max :

    79.5

    [774212 values with dtype=float64]

  • unfolded_differential_phase
    (azimuth, range)
    float64
    ...

    long_name :

    Unfolded differential propagation phase shift

    units :

    degree

    standard_name :

    differential_phase_hv

    [774212 values with dtype=float64]

  • corrected_differential_phase
    (azimuth, range)
    float64
    ...

    long_name :

    Corrected differential propagation phase shift

    units :

    degree

    standard_name :

    differential_phase_hv

    valid_min :

    0.0

    valid_max :

    400.0

    [774212 values with dtype=float64]

  • filtered_corrected_differential_phase
    (azimuth, range)
    float64
    ...

    long_name :

    Filtered Corrected Differential Phase

    units :

    degree

    standard_name :

    differential_phase_hv

    valid_min :

    0.0

    valid_max :

    400.0

    [774212 values with dtype=float64]

  • corrected_specific_diff_phase
    (azimuth, range)
    float64
    ...

    long_name :

    Specific differential phase (KDP)

    units :

    degrees/km

    standard_name :

    specific_differential_phase_hv

    [774212 values with dtype=float64]

  • filtered_corrected_specific_diff_phase
    (azimuth, range)
    float64
    ...

    long_name :

    Filtered Corrected Specific differential phase (KDP)

    units :

    degrees/km

    standard_name :

    specific_differential_phase_hv

    [774212 values with dtype=float64]

  • corrected_differential_reflectivity
    (azimuth, range)
    float64
    ...

    long_name :

    Corrected differential reflectivity

    units :

    dB

    standard_name :

    corrected_log_differential_reflectivity_hv

    [774212 values with dtype=float64]

  • corrected_reflectivity
    (azimuth, range)
    float64
    ...

    long_name :

    Corrected reflectivity

    units :

    dBZ

    standard_name :

    corrected_equivalent_reflectivity_factor

    [774212 values with dtype=float64]

  • height_over_iso0
    (azimuth, range)
    float32
    ...

    long_name :

    Height of radar beam over freezing level

    units :

    m

    standard_name :

    height

    [774212 values with dtype=float32]

  • specific_attenuation
    (azimuth, range)
    float64
    ...

    long_name :

    Specific attenuation

    units :

    dB/km

    standard_name :

    specific_attenuation

    valid_min :

    0.0

    valid_max :

    1.0

    [774212 values with dtype=float64]

  • path_integrated_attenuation
    (azimuth, range)
    float64
    ...

    long_name :

    Path Integrated Attenuation

    units :

    dB

    [774212 values with dtype=float64]

  • specific_differential_attenuation
    (azimuth, range)
    float64
    ...

    long_name :

    Specific Differential Attenuation

    units :

    dB/km

    [774212 values with dtype=float64]

  • path_integrated_differential_attenuation
    (azimuth, range)
    float64
    ...

    long_name :

    Path Integrated Differential Attenuation

    units :

    dB

    [774212 values with dtype=float64]

  • rain_rate_A
    (azimuth, range)
    float64
    ...

    long_name :

    Rainfall Rate from Specific Attenuation

    units :

    mm/hr

    standard_name :

    rainfall_rate

    comment :

    Rain rate calculated from specific_attenuation, R=43.5*specific_attenuation**0.79, note R=0.0 where norm coherent power < 0.4 or rhohv < 0.8

    valid_min :

    0.0

    valid_max :

    400.0

    [774212 values with dtype=float64]

  • snow_rate_ws2012
    (azimuth, range)
    float64
    ...

    long_name :

    Snowfall rate from Z using Wolf and Snider (2012)

    units :

    mm/h

    standard_name :

    snowfall_rate

    valid_min :

    0

    valid_max :

    500

    swe_ratio :

    13.699

    A :

    110

    B :

    2

    [774212 values with dtype=float64]

  • snow_rate_ws88diw
    (azimuth, range)
    float64
    ...

    long_name :

    Snowfall rate from Z using WSR 88D High Plains

    units :

    mm/h

    standard_name :

    snowfall_rate

    valid_min :

    0

    valid_max :

    500

    swe_ratio :

    13.699

    A :

    40

    B :

    2

    [774212 values with dtype=float64]

  • snow_rate_m2009_1
    (azimuth, range)
    float64
    ...

    long_name :

    Snowfall rate from Z using Matrosov et al.(2009) Braham(1990) 1

    units :

    mm/h

    standard_name :

    snowfall_rate

    valid_min :

    0

    valid_max :

    500

    swe_ratio :

    13.699

    A :

    67

    B :

    1.28

    [774212 values with dtype=float64]

  • snow_rate_m2009_2
    (azimuth, range)
    float64
    ...

    long_name :

    Snowfall rate from Z using Matrosov et al.(2009) Braham(1990) 2

    units :

    mm/h

    standard_name :

    snowfall_rate

    valid_min :

    0

    valid_max :

    500

    swe_ratio :

    13.699

    A :

    114

    B :

    1.39

    [774212 values with dtype=float64]

  • sweep_number
    ()
    int32
    ...

    long_name :

    Sweep index number 0 based

    units :

    1

    [1 values with dtype=int32]

  • sweep_fixed_angle
    ()
    float32
    ...

    long_name :

    Ray Target Fixed Angle

    units :

    degree

    [1 values with dtype=float32]

  • sweep_mode
    ()
    <U188
    ...

    [1 values with dtype=<U188]

  • nyquist_velocity
    (azimuth)
    float64
    ...

    long_name :

    Nyquist velocity

    units :

    m/s

    standard_name :

    nyquist_velocity

    [1159 values with dtype=float64]

• Indexes: (2)
  • range
    PandasIndex

    PandasIndex(Index([ 306.8816833496094,  366.8226318359375,  426.7635803222656,
           486.70452880859375,  546.6454467773438,    606.58642578125,
                 666.52734375,  726.4683227539062,  786.4093017578125,
            846.3502197265625,
           ...
               39748.02734375,        39807.96875,        39867.90625,
                39927.8515625,     39987.79296875,     40047.73046875,
                 40107.671875,       40167.609375,      40227.5546875,
               40287.49609375],
          dtype='float32', name='range', length=668))

  • azimuth
    PandasIndex

    PandasIndex(Index([0.05238281190395355, 0.11280761659145355, 0.12506836652755737,
           0.12506836652755737, 0.15125976502895355, 0.17872558534145355,
           0.18971191346645355, 0.20069824159145355, 0.20069824159145355,
           0.20619140565395355,
           ...
             358.5032958984375,   358.7230224609375,   358.9427490234375,
             359.1514892578125,     359.32177734375,   359.4920654296875,
              359.640380859375,     359.76123046875,    359.882080078125,
             359.9754638671875],
          dtype='float32', name='azimuth', length=1159))

• Attributes: (0)

or the full volume!

dt = xd.io.open_cfradial1_datatree(file)
dt

<xarray.DatasetView> Size: 1kB
Dimensions:              (sweep: 1)
Dimensions without coordinates: sweep
Data variables:
    sweep_group_name     (sweep) <U7 28B 'sweep_0'
    sweep_fixed_angle    (sweep) float32 4B ...
    latitude             float64 8B ...
    longitude            float64 8B ...
    altitude             float64 8B ...
    time_coverage_start  |S192 192B ...
    time_coverage_end    |S192 192B ...
    volume_number        int32 4B ...
    platform_type        |S192 192B ...
    instrument_type      |S192 192B ...
    primary_axis         |S192 192B ...
Attributes:
    Conventions:  CF/Radial instrument_parameters ARM-1.3
    comment:      This is highly experimental and initial data. There are man...
    references:   See XSAPR Instrument Handbook
    source:       Atmospheric Radiation Measurement (ARM) program X-band Scan...
    institution:  U.S. Department of Energy Atmospheric Radiation Measurement...
    history:      created by jrobrien on cirrus127.ccs.ornl.gov at 2022-09-26...

datatree.DataTree

• Groups: (3)
  <xarray.DatasetView> Size: 0B
  Dimensions:  ()
  Data variables:
      *empty*

  radar_parameters

  • Groups: (0)
  • Dimensions:
  • Coordinates: (0)
  • Data variables: (0)
  • Attributes: (0)

  <xarray.DatasetView> Size: 0B
  Dimensions:  ()
  Data variables:
      *empty*

  georeferencing_correction

  • Groups: (0)
  • Dimensions:
  • Coordinates: (0)
  • Data variables: (0)
  • Attributes: (0)

  <xarray.DatasetView> Size: 195MB
  Dimensions:                                   (azimuth: 1159, range: 668)
  Coordinates:
      time                                      (azimuth) datetime64[ns] 9kB 20...
    * range                                     (range) float32 3kB 306.9 ... 4...
      elevation                                 (azimuth) float32 5kB ...
    * azimuth                                   (azimuth) float32 5kB 0.05238 ....
      latitude                                  float64 8B ...
      longitude                                 float64 8B ...
      altitude                                  float64 8B ...
  Data variables: (12/37)
      DBZ                                       (azimuth, range) float64 6MB ...
      VEL                                       (azimuth, range) float64 6MB ...
      WIDTH                                     (azimuth, range) float64 6MB ...
      ZDR                                       (azimuth, range) float64 6MB ...
      PHIDP                                     (azimuth, range) float64 6MB ...
      RHOHV                                     (azimuth, range) float64 6MB ...
      ...                                        ...
      snow_rate_m2009_1                         (azimuth, range) float64 6MB ...
      snow_rate_m2009_2                         (azimuth, range) float64 6MB ...
      sweep_number                              int32 4B ...
      sweep_fixed_angle                         float32 4B ...
      sweep_mode                                <U188 752B 'azimuth_surveillanc...
      nyquist_velocity                          (azimuth) float64 9kB ...

  sweep_0

  • Groups: (0)
  • Dimensions:
    • azimuth: 1159
    • range: 668
  • Coordinates: (7)
    • time
      (azimuth)
      datetime64[ns]
      2022-03-14T02:18:06 ... 2022-03-...

      long_name :

      Time in Seconds from Volume Start

      standard_name :

      time

      array(['2022-03-14T02:18:06.000000000', '2022-03-14T02:18:06.000000000',
             '2022-03-14T02:17:35.000000000', ..., '2022-03-14T02:18:06.000000000',
             '2022-03-14T02:18:06.000000000', '2022-03-14T02:18:06.000000000'],
            dtype='datetime64[ns]')

    • range
      (range)
      float32
      306.9 366.8 ... 4.023e+04 4.029e+04

      long_name :

      Range to measurement volume

      units :

      meter

      standard_name :

      projection_range_coordinate

      spacing_is_constant :

      true

      axis :

      radial_range_coordinate

      meters_to_center_of_first_gate :

      -112.6891

      meters_between_gates :

      59.94095

      array([  306.88168,   366.82263,   426.76358, ..., 40167.61   , 40227.555  ,
             40287.496  ], dtype=float32)

    • elevation
      (azimuth)
      float32
      ...

      long_name :

      Elevation angle from horizontal plane

      units :

      degree

      axis :

      radial_elevation_coordinate

      standard_name :

      sensor_to_target_elevation_angle

      [1159 values with dtype=float32]

    • azimuth
      (azimuth)
      float32
      0.05238 0.1128 ... 359.9 360.0

      long_name :

      Azimuth Angle from True North

      units :

      degree

      axis :

      radial_azimuth_coordinate

      standard_name :

      sensor_to_target_azimuth_angle

      array([5.238281e-02, 1.128076e-01, 1.250684e-01, ..., 3.597612e+02,
             3.598821e+02, 3.599755e+02], dtype=float32)

    • latitude
      ()
      float64
      ...

      long_name :

      Latitude

      units :

      degree_N

      standard_name :

      latitude

      valid_min :

      -90.0

      valid_max :

      90.0

      [1 values with dtype=float64]

    • longitude
      ()
      float64
      ...

      long_name :

      Longitude

      units :

      degree_E

      standard_name :

      longitude

      valid_min :

      -180.0

      valid_max :

      180.0

      [1 values with dtype=float64]

    • altitude
      ()
      float64
      ...

      long_name :

      Altitude

      units :

      m

      standard_name :

      altitude

      [1 values with dtype=float64]

  • Data variables: (37)
    • DBZ
      (azimuth, range)
      float64
      ...

      long_name :

      Equaivalent_radar_reflectiivity_factor

      units :

      dBZ

      standard_name :

      equivalent_reflectivity_factor

      [774212 values with dtype=float64]

    • VEL
      (azimuth, range)
      float64
      ...

      long_name :

      Radial Doppler Velocity, Positive for Motion Away from Instrument

      units :

      m/s

      standard_name :

      radial_velocity_of_scatterers_away_from_instruments

      [774212 values with dtype=float64]

    • WIDTH
      (azimuth, range)
      float64
      ...

      long_name :

      Spectral Width

      units :

      m/s

      standard_name :

      doppler_spectrum_width

      [774212 values with dtype=float64]

    • ZDR
      (azimuth, range)
      float64
      ...

      long_name :

      Differential Reflectivity

      units :

      dB

      standard_name :

      log_differential_reflectivity_hv

      [774212 values with dtype=float64]

    • PHIDP
      (azimuth, range)
      float64
      ...

      long_name :

      Differential Phase

      units :

      degree

      standard_name :

      differential_phase_hv

      [774212 values with dtype=float64]

    • RHOHV
      (azimuth, range)
      float64
      ...

      long_name :

      Cross-Polar Correlation Ratio

      units :

      1

      standard_name :

      cross_correlation_ratio_hv

      [774212 values with dtype=float64]

    • NCP
      (azimuth, range)
      float64
      ...

      long_name :

      Normalized Coherent Power, also known as SQI

      units :

      1

      standard_name :

      normalized_coherent_power

      [774212 values with dtype=float64]

    • DBZhv
      (azimuth, range)
      float64
      ...

      long_name :

      Equivalent Reflectivity Factor HV

      units :

      dBZ

      standard_name :

      equivalent_reflectivity_factor_hv

      [774212 values with dtype=float64]

    • cbb_flag
      (azimuth, range)
      float64
      ...

      long_name :

      Cumulative Beam Block Fraction Flag

      units :

      1

      comment :

      Cumulative beam block flag due to terrain.

      [774212 values with dtype=float64]

    • sounding_temperature
      (azimuth, range)
      float32
      ...

      long_name :

      Interpolated profile

      units :

      degC

      standard_name :

      interpolated_profile

      [774212 values with dtype=float32]

    • height
      (azimuth, range)
      float32
      ...

      long_name :

      Height of radar beam

      units :

      m

      standard_name :

      height

      [774212 values with dtype=float32]

    • signal_to_noise_ratio
      (azimuth, range)
      float64
      ...

      long_name :

      Signal to Noise Ratio

      units :

      dB

      standard_name :

      signal_to_noise_ratio

      [774212 values with dtype=float64]

    • velocity_texture
      (azimuth, range)
      float64
      ...

      long_name :

      Mean dopper velocity

      units :

      m/s

      standard_name :

      radial_velocity_of_scatterers_away_from_instrument

      [774212 values with dtype=float64]

    • gate_id
      (azimuth, range)
      int64
      ...

      long_name :

      Classification of dominant scatterer

      units :

      1

      notes :

      0:multi_trip,1:rain,2:snow,3:no_scatter,4:melting,5:clutter,6:terrain_blockage

      valid_max :

      6

      valid_min :

      0

      flag_values :

      0, 1, 2, 3, 4, 5, 6

      flag_meanings :

      multi_trip rain snow no_scatter melting clutter terrain_blockage

      [774212 values with dtype=int64]

    • simulated_velocity
      (azimuth, range)
      float64
      ...

      long_name :

      Simulated mean doppler velocity

      units :

      m/s

      standard_name :

      radial_velocity_of_scatterers_away_from_instrument

      [774212 values with dtype=float64]

    • corrected_velocity
      (azimuth, range)
      float64
      ...

      long_name :

      Corrected mean doppler velocity

      units :

      m/s

      standard_name :

      corrected_radial_velocity_of_scatterers_away_from_instrument

      valid_min :

      -79.5

      valid_max :

      79.5

      [774212 values with dtype=float64]

    • unfolded_differential_phase
      (azimuth, range)
      float64
      ...

      long_name :

      Unfolded differential propagation phase shift

      units :

      degree

      standard_name :

      differential_phase_hv

      [774212 values with dtype=float64]

    • corrected_differential_phase
      (azimuth, range)
      float64
      ...

      long_name :

      Corrected differential propagation phase shift

      units :

      degree

      standard_name :

      differential_phase_hv

      valid_min :

      0.0

      valid_max :

      400.0

      [774212 values with dtype=float64]

    • filtered_corrected_differential_phase
      (azimuth, range)
      float64
      ...

      long_name :

      Filtered Corrected Differential Phase

      units :

      degree

      standard_name :

      differential_phase_hv

      valid_min :

      0.0

      valid_max :

      400.0

      [774212 values with dtype=float64]

    • corrected_specific_diff_phase
      (azimuth, range)
      float64
      ...

      long_name :

      Specific differential phase (KDP)

      units :

      degrees/km

      standard_name :

      specific_differential_phase_hv

      [774212 values with dtype=float64]

    • filtered_corrected_specific_diff_phase
      (azimuth, range)
      float64
      ...

      long_name :

      Filtered Corrected Specific differential phase (KDP)

      units :

      degrees/km

      standard_name :

      specific_differential_phase_hv

      [774212 values with dtype=float64]

    • corrected_differential_reflectivity
      (azimuth, range)
      float64
      ...

      long_name :

      Corrected differential reflectivity

      units :

      dB

      standard_name :

      corrected_log_differential_reflectivity_hv

      [774212 values with dtype=float64]

    • corrected_reflectivity
      (azimuth, range)
      float64
      ...

      long_name :

      Corrected reflectivity

      units :

      dBZ

      standard_name :

      corrected_equivalent_reflectivity_factor

      [774212 values with dtype=float64]

    • height_over_iso0
      (azimuth, range)
      float32
      ...

      long_name :

      Height of radar beam over freezing level

      units :

      m

      standard_name :

      height

      [774212 values with dtype=float32]

    • specific_attenuation
      (azimuth, range)
      float64
      ...

      long_name :

      Specific attenuation

      units :

      dB/km

      standard_name :

      specific_attenuation

      valid_min :

      0.0

      valid_max :

      1.0

      [774212 values with dtype=float64]

    • path_integrated_attenuation
      (azimuth, range)
      float64
      ...

      long_name :

      Path Integrated Attenuation

      units :

      dB

      [774212 values with dtype=float64]

    • specific_differential_attenuation
      (azimuth, range)
      float64
      ...

      long_name :

      Specific Differential Attenuation

      units :

      dB/km

      [774212 values with dtype=float64]

    • path_integrated_differential_attenuation
      (azimuth, range)
      float64
      ...

      long_name :

      Path Integrated Differential Attenuation

      units :

      dB

      [774212 values with dtype=float64]

    • rain_rate_A
      (azimuth, range)
      float64
      ...

      long_name :

      Rainfall Rate from Specific Attenuation

      units :

      mm/hr

      standard_name :

      rainfall_rate

      comment :

      Rain rate calculated from specific_attenuation, R=43.5*specific_attenuation**0.79, note R=0.0 where norm coherent power < 0.4 or rhohv < 0.8

      valid_min :

      0.0

      valid_max :

      400.0

      [774212 values with dtype=float64]

    • snow_rate_ws2012
      (azimuth, range)
      float64
      ...

      long_name :

      Snowfall rate from Z using Wolf and Snider (2012)

      units :

      mm/h

      standard_name :

      snowfall_rate

      valid_min :

      0

      valid_max :

      500

      swe_ratio :

      13.699

      A :

      110

      B :

      2

      [774212 values with dtype=float64]

    • snow_rate_ws88diw
      (azimuth, range)
      float64
      ...

      long_name :

      Snowfall rate from Z using WSR 88D High Plains

      units :

      mm/h

      standard_name :

      snowfall_rate

      valid_min :

      0

      valid_max :

      500

      swe_ratio :

      13.699

      A :

      40

      B :

      2

      [774212 values with dtype=float64]

    • snow_rate_m2009_1
      (azimuth, range)
      float64
      ...

      long_name :

      Snowfall rate from Z using Matrosov et al.(2009) Braham(1990) 1

      units :

      mm/h

      standard_name :

      snowfall_rate

      valid_min :

      0

      valid_max :

      500

      swe_ratio :

      13.699

      A :

      67

      B :

      1.28

      [774212 values with dtype=float64]

    • snow_rate_m2009_2
      (azimuth, range)
      float64
      ...

      long_name :

      Snowfall rate from Z using Matrosov et al.(2009) Braham(1990) 2

      units :

      mm/h

      standard_name :

      snowfall_rate

      valid_min :

      0

      valid_max :

      500

      swe_ratio :

      13.699

      A :

      114

      B :

      1.39

      [774212 values with dtype=float64]

    • sweep_number
      ()
      int32
      ...

      long_name :

      Sweep index number 0 based

      units :

      1

      [1 values with dtype=int32]

    • sweep_fixed_angle
      ()
      float32
      ...

      long_name :

      Ray Target Fixed Angle

      units :

      degree

      [1 values with dtype=float32]

    • sweep_mode
      ()
      <U188
      'azimuth_surveillance\x00\x00\x0...

      array('azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance',
            dtype='<U188')

    • nyquist_velocity
      (azimuth)
      float64
      ...

      long_name :

      Nyquist velocity

      units :

      m/s

      standard_name :

      nyquist_velocity

      [1159 values with dtype=float64]

  • Attributes: (0)

• Dimensions:
  • sweep: 1
• Coordinates: (0)
• Data variables: (11)
  • sweep_group_name
    (sweep)
    <U7
    'sweep_0'

    array(['sweep_0'], dtype='<U7')

  • sweep_fixed_angle
    (sweep)
    float32
    ...

    long_name :

    Ray Target Fixed Angle

    units :

    degree

    [1 values with dtype=float32]

  • latitude
    ()
    float64
    ...

    long_name :

    Latitude

    units :

    degree_N

    standard_name :

    latitude

    valid_min :

    -90.0

    valid_max :

    90.0

    [1 values with dtype=float64]

  • longitude
    ()
    float64
    ...

    long_name :

    Longitude

    units :

    degree_E

    standard_name :

    longitude

    valid_min :

    -180.0

    valid_max :

    180.0

    [1 values with dtype=float64]

  • altitude
    ()
    float64
    ...

    long_name :

    Altitude

    units :

    m

    standard_name :

    altitude

    [1 values with dtype=float64]

  • time_coverage_start
    ()
    |S192
    ...

    long_name :

    UTC time of first ray in the file

    units :

    unitless

    [1 values with dtype=|S192]

  • time_coverage_end
    ()
    |S192
    ...

    long_name :

    UTC time of last ray in the file

    units :

    unitless

    [1 values with dtype=|S192]

  • volume_number
    ()
    int32
    ...

    long_name :

    Volume number

    units :

    unitless

    [1 values with dtype=int32]

  • platform_type
    ()
    |S192
    ...

    long_name :

    Platform type

    [1 values with dtype=|S192]

  • instrument_type
    ()
    |S192
    ...

    long_name :

    Instrument type

    [1 values with dtype=|S192]

  • primary_axis
    ()
    |S192
    ...

    long_name :

    Primary axis

    [1 values with dtype=|S192]

• Attributes: (6)

  Conventions :

  CF/Radial instrument_parameters ARM-1.3

  comment :

  This is highly experimental and initial data. There are many known and unknown issues. Please do not use before contacting the Translator responsible scollis@anl.gov

  references :

  See XSAPR Instrument Handbook

  source :

  Atmospheric Radiation Measurement (ARM) program X-band Scanning ARM Precipitation Radar (XSAPR)

  institution :

  U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Climate Research Facility

  history :

  created by jrobrien on cirrus127.ccs.ornl.gov at 2022-09-26T13:18:32.369353 using Py-ART

Remove duplicate rays - this will help later!

dt["sweep_0"] = xd.util.remove_duplicate_rays(dt["sweep_0"])

Create a quick plot of the data

dt = dt.xradar.georeference()
dt["sweep_0"]

<xarray.DatasetView> Size: 202MB
Dimensions:                                   (azimuth: 1147, range: 668)
Coordinates:
    time                                      (azimuth) datetime64[ns] 9kB 20...
  * range                                     (range) float32 3kB 306.9 ... 4...
    elevation                                 (azimuth) float32 5kB 5.988 ......
  * azimuth                                   (azimuth) float32 5kB 0.05238 ....
    latitude                                  float64 8B 38.9
    longitude                                 float64 8B -106.9
    altitude                                  float64 8B 3.149e+03
    crs_wkt                                   int64 8B 0
    x                                         (azimuth, range) float32 3MB 0....
    y                                         (azimuth, range) float32 3MB 30...
    z                                         (azimuth, range) float32 3MB 3....
Data variables: (12/37)
    DBZ                                       (azimuth, range) float64 6MB ...
    VEL                                       (azimuth, range) float64 6MB ...
    WIDTH                                     (azimuth, range) float64 6MB ...
    ZDR                                       (azimuth, range) float64 6MB ...
    PHIDP                                     (azimuth, range) float64 6MB ...
    RHOHV                                     (azimuth, range) float64 6MB ...
    ...                                        ...
    snow_rate_m2009_1                         (azimuth, range) float64 6MB ...
    snow_rate_m2009_2                         (azimuth, range) float64 6MB ...
    sweep_number                              int32 4B ...
    sweep_fixed_angle                         float32 4B ...
    sweep_mode                                <U188 752B 'azimuth_surveillanc...
    nyquist_velocity                          (azimuth) float64 9kB ...

datatree.DataTree

• Groups: (0)
• Dimensions:
  • azimuth: 1147
  • range: 668
• Coordinates: (11)
  • time
    (azimuth)
    datetime64[ns]
    2022-03-14T02:18:06 ... 2022-03-...

    long_name :

    Time in Seconds from Volume Start

    standard_name :

    time

    array(['2022-03-14T02:18:06.000000000', '2022-03-14T02:18:06.000000000',
           '2022-03-14T02:17:35.000000000', ..., '2022-03-14T02:18:06.000000000',
           '2022-03-14T02:18:06.000000000', '2022-03-14T02:18:06.000000000'],
          dtype='datetime64[ns]')

  • range
    (range)
    float32
    306.9 366.8 ... 4.023e+04 4.029e+04

    long_name :

    Range to measurement volume

    units :

    meter

    standard_name :

    projection_range_coordinate

    spacing_is_constant :

    true

    axis :

    radial_range_coordinate

    meters_to_center_of_first_gate :

    -112.6891

    meters_between_gates :

    59.94095

    array([  306.88168,   366.82263,   426.76358, ..., 40167.61   , 40227.555  ,
           40287.496  ], dtype=float32)

  • elevation
    (azimuth)
    float32
    5.988 5.988 5.938 ... 5.988 5.988

    long_name :

    Elevation angle from horizontal plane

    units :

    degree

    axis :

    radial_elevation_coordinate

    standard_name :

    sensor_to_target_elevation_angle

    array([5.987549, 5.987549, 5.93811 , ..., 5.987549, 5.987549, 5.987549],
          dtype=float32)

  • azimuth
    (azimuth)
    float32
    0.05238 0.1128 ... 359.9 360.0

    long_name :

    Azimuth Angle from True North

    units :

    degree

    axis :

    radial_azimuth_coordinate

    standard_name :

    sensor_to_target_azimuth_angle

    array([5.238281e-02, 1.128076e-01, 1.250684e-01, ..., 3.597612e+02,
           3.598821e+02, 3.599755e+02], dtype=float32)

  • latitude
    ()
    float64
    38.9

    long_name :

    Latitude

    units :

    degree_N

    standard_name :

    latitude

    valid_min :

    -90.0

    valid_max :

    90.0

    array(38.89838)

  • longitude
    ()
    float64
    -106.9

    long_name :

    Longitude

    units :

    degree_E

    standard_name :

    longitude

    valid_min :

    -180.0

    valid_max :

    180.0

    array(-106.943214)

  • altitude
    ()
    float64
    3.149e+03

    long_name :

    Altitude

    units :

    m

    standard_name :

    altitude

    array(3149.199951)

  • crs_wkt
    ()
    int64
    0

    crs_wkt :

    PROJCRS["unknown",BASEGEOGCRS["unknown",DATUM["World Geodetic System 1984",ELLIPSOID["WGS 84",6378137,298.257223563,LENGTHUNIT["metre",1]],ID["EPSG",6326]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8901]]],CONVERSION["unknown",METHOD["Modified Azimuthal Equidistant",ID["EPSG",9832]],PARAMETER["Latitude of natural origin",38.898380279541,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8801]],PARAMETER["Longitude of natural origin",-106.943214416504,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8802]],PARAMETER["False easting",0,LENGTHUNIT["metre",1],ID["EPSG",8806]],PARAMETER["False northing",0,LENGTHUNIT["metre",1],ID["EPSG",8807]]],CS[Cartesian,2],AXIS["(E)",east,ORDER[1],LENGTHUNIT["metre",1,ID["EPSG",9001]]],AXIS["(N)",north,ORDER[2],LENGTHUNIT["metre",1,ID["EPSG",9001]]]]

    semi_major_axis :

    6378137.0

    semi_minor_axis :

    6356752.314245179

    inverse_flattening :

    298.257223563

    reference_ellipsoid_name :

    WGS 84

    longitude_of_prime_meridian :

    0.0

    prime_meridian_name :

    Greenwich

    geographic_crs_name :

    unknown

    horizontal_datum_name :

    World Geodetic System 1984

    projected_crs_name :

    unknown

    grid_mapping_name :

    azimuthal_equidistant

    latitude_of_projection_origin :

    38.898380279541016

    longitude_of_projection_origin :

    -106.9432144165039

    false_easting :

    0.0

    false_northing :

    0.0

    array(0)

  • x
    (azimuth, range)
    float32
    0.2789 0.3334 ... -17.13 -17.15

    standard_name :

    east_west_distance_from_radar

    units :

    meters

    array([[ 2.7893224e-01,  3.3341372e-01,  3.8789520e-01, ...,
             3.6491188e+01,  3.6545620e+01,  3.6600048e+01],
           [ 6.0068691e-01,  7.1801394e-01,  8.3534104e-01, ...,
             7.8584595e+01,  7.8701813e+01,  7.8819031e+01],
           [ 6.6603380e-01,  7.9612476e-01,  9.2621547e-01, ...,
             8.7133934e+01,  8.7263901e+01,  8.7393867e+01],
           ...,
           [-1.2714366e+00, -1.5197754e+00, -1.7681143e+00, ...,
            -1.6633513e+02, -1.6658322e+02, -1.6683133e+02],
           [-6.2798256e-01, -7.5064105e-01, -8.7329954e-01, ...,
            -8.2155540e+01, -8.2278084e+01, -8.2400627e+01],
           [-1.3073300e-01, -1.5626796e-01, -1.8180293e-01, ...,
            -1.7103086e+01, -1.7128597e+01, -1.7154108e+01]], dtype=float32)

  • y
    (azimuth, range)
    float32
    305.1 364.7 ... 3.997e+04 4.003e+04

    standard_name :

    north_south_distance_from_radar

    units :

    meters

    array([[  305.09314,   364.6844 ,   424.27563, ..., 39913.676  ,
            39973.21   , 40032.746  ],
           [  305.09265,   364.6838 ,   424.275  , ..., 39913.613  ,
            39973.15   , 40032.684  ],
           [  305.12003,   364.71664,   424.31314, ..., 39917.355  ,
            39976.9    , 40036.438  ],
           ...,
           [  305.0906 ,   364.68137,   424.27213, ..., 39913.344  ,
            39972.88   , 40032.414  ],
           [  305.09262,   364.68375,   424.2749 , ..., 39913.605  ,
            39973.14   , 40032.676  ],
           [  305.09323,   364.6845 ,   424.27576, ..., 39913.688  ,
            39973.223  , 40032.758  ]], dtype=float32)

  • z
    (azimuth, range)
    float32
    3.181e+03 3.188e+03 ... 7.446e+03

    standard_name :

    height_above_ground

    units :

    meters

    array([[3181., 3188., 3194., ..., 7433., 7440., 7446.],
           [3181., 3188., 3194., ..., 7433., 7440., 7446.],
           [3181., 3187., 3193., ..., 7399., 7405., 7411.],
           ...,
           [3181., 3188., 3194., ..., 7433., 7440., 7446.],
           [3181., 3188., 3194., ..., 7433., 7440., 7446.],
           [3181., 3188., 3194., ..., 7433., 7440., 7446.]], dtype=float32)

• Data variables: (37)
  • DBZ
    (azimuth, range)
    float64
    ...

    long_name :

    Equaivalent_radar_reflectiivity_factor

    units :

    dBZ

    standard_name :

    equivalent_reflectivity_factor

    [766196 values with dtype=float64]

  • VEL
    (azimuth, range)
    float64
    ...

    long_name :

    Radial Doppler Velocity, Positive for Motion Away from Instrument

    units :

    m/s

    standard_name :

    radial_velocity_of_scatterers_away_from_instruments

    [766196 values with dtype=float64]

  • WIDTH
    (azimuth, range)
    float64
    ...

    long_name :

    Spectral Width

    units :

    m/s

    standard_name :

    doppler_spectrum_width

    [766196 values with dtype=float64]

  • ZDR
    (azimuth, range)
    float64
    ...

    long_name :

    Differential Reflectivity

    units :

    dB

    standard_name :

    log_differential_reflectivity_hv

    [766196 values with dtype=float64]

  • PHIDP
    (azimuth, range)
    float64
    ...

    long_name :

    Differential Phase

    units :

    degree

    standard_name :

    differential_phase_hv

    [766196 values with dtype=float64]

  • RHOHV
    (azimuth, range)
    float64
    ...

    long_name :

    Cross-Polar Correlation Ratio

    units :

    1

    standard_name :

    cross_correlation_ratio_hv

    [766196 values with dtype=float64]

  • NCP
    (azimuth, range)
    float64
    ...

    long_name :

    Normalized Coherent Power, also known as SQI

    units :

    1

    standard_name :

    normalized_coherent_power

    [766196 values with dtype=float64]

  • DBZhv
    (azimuth, range)
    float64
    ...

    long_name :

    Equivalent Reflectivity Factor HV

    units :

    dBZ

    standard_name :

    equivalent_reflectivity_factor_hv

    [766196 values with dtype=float64]

  • cbb_flag
    (azimuth, range)
    float64
    ...

    long_name :

    Cumulative Beam Block Fraction Flag

    units :

    1

    comment :

    Cumulative beam block flag due to terrain.

    [766196 values with dtype=float64]

  • sounding_temperature
    (azimuth, range)
    float32
    ...

    long_name :

    Interpolated profile

    units :

    degC

    standard_name :

    interpolated_profile

    [766196 values with dtype=float32]

  • height
    (azimuth, range)
    float32
    ...

    long_name :

    Height of radar beam

    units :

    m

    standard_name :

    height

    [766196 values with dtype=float32]

  • signal_to_noise_ratio
    (azimuth, range)
    float64
    ...

    long_name :

    Signal to Noise Ratio

    units :

    dB

    standard_name :

    signal_to_noise_ratio

    [766196 values with dtype=float64]

  • velocity_texture
    (azimuth, range)
    float64
    ...

    long_name :

    Mean dopper velocity

    units :

    m/s

    standard_name :

    radial_velocity_of_scatterers_away_from_instrument

    [766196 values with dtype=float64]

  • gate_id
    (azimuth, range)
    int64
    ...

    long_name :

    Classification of dominant scatterer

    units :

    1

    notes :

    0:multi_trip,1:rain,2:snow,3:no_scatter,4:melting,5:clutter,6:terrain_blockage

    valid_max :

    6

    valid_min :

    0

    flag_values :

    0, 1, 2, 3, 4, 5, 6

    flag_meanings :

    multi_trip rain snow no_scatter melting clutter terrain_blockage

    [766196 values with dtype=int64]

  • simulated_velocity
    (azimuth, range)
    float64
    ...

    long_name :

    Simulated mean doppler velocity

    units :

    m/s

    standard_name :

    radial_velocity_of_scatterers_away_from_instrument

    [766196 values with dtype=float64]

  • corrected_velocity
    (azimuth, range)
    float64
    ...

    long_name :

    Corrected mean doppler velocity

    units :

    m/s

    standard_name :

    corrected_radial_velocity_of_scatterers_away_from_instrument

    valid_min :

    -79.5

    valid_max :

    79.5

    [766196 values with dtype=float64]

  • unfolded_differential_phase
    (azimuth, range)
    float64
    ...

    long_name :

    Unfolded differential propagation phase shift

    units :

    degree

    standard_name :

    differential_phase_hv

    [766196 values with dtype=float64]

  • corrected_differential_phase
    (azimuth, range)
    float64
    ...

    long_name :

    Corrected differential propagation phase shift

    units :

    degree

    standard_name :

    differential_phase_hv

    valid_min :

    0.0

    valid_max :

    400.0

    [766196 values with dtype=float64]

  • filtered_corrected_differential_phase
    (azimuth, range)
    float64
    ...

    long_name :

    Filtered Corrected Differential Phase

    units :

    degree

    standard_name :

    differential_phase_hv

    valid_min :

    0.0

    valid_max :

    400.0

    [766196 values with dtype=float64]

  • corrected_specific_diff_phase
    (azimuth, range)
    float64
    ...

    long_name :

    Specific differential phase (KDP)

    units :

    degrees/km

    standard_name :

    specific_differential_phase_hv

    [766196 values with dtype=float64]

  • filtered_corrected_specific_diff_phase
    (azimuth, range)
    float64
    ...

    long_name :

    Filtered Corrected Specific differential phase (KDP)

    units :

    degrees/km

    standard_name :

    specific_differential_phase_hv

    [766196 values with dtype=float64]

  • corrected_differential_reflectivity
    (azimuth, range)
    float64
    ...

    long_name :

    Corrected differential reflectivity

    units :

    dB

    standard_name :

    corrected_log_differential_reflectivity_hv

    [766196 values with dtype=float64]

  • corrected_reflectivity
    (azimuth, range)
    float64
    ...

    long_name :

    Corrected reflectivity

    units :

    dBZ

    standard_name :

    corrected_equivalent_reflectivity_factor

    [766196 values with dtype=float64]

  • height_over_iso0
    (azimuth, range)
    float32
    ...

    long_name :

    Height of radar beam over freezing level

    units :

    m

    standard_name :

    height

    [766196 values with dtype=float32]

  • specific_attenuation
    (azimuth, range)
    float64
    ...

    long_name :

    Specific attenuation

    units :

    dB/km

    standard_name :

    specific_attenuation

    valid_min :

    0.0

    valid_max :

    1.0

    [766196 values with dtype=float64]

  • path_integrated_attenuation
    (azimuth, range)
    float64
    ...

    long_name :

    Path Integrated Attenuation

    units :

    dB

    [766196 values with dtype=float64]

  • specific_differential_attenuation
    (azimuth, range)
    float64
    ...

    long_name :

    Specific Differential Attenuation

    units :

    dB/km

    [766196 values with dtype=float64]

  • path_integrated_differential_attenuation
    (azimuth, range)
    float64
    ...

    long_name :

    Path Integrated Differential Attenuation

    units :

    dB

    [766196 values with dtype=float64]

  • rain_rate_A
    (azimuth, range)
    float64
    ...

    long_name :

    Rainfall Rate from Specific Attenuation

    units :

    mm/hr

    standard_name :

    rainfall_rate

    comment :

    Rain rate calculated from specific_attenuation, R=43.5*specific_attenuation**0.79, note R=0.0 where norm coherent power < 0.4 or rhohv < 0.8

    valid_min :

    0.0

    valid_max :

    400.0

    [766196 values with dtype=float64]

  • snow_rate_ws2012
    (azimuth, range)
    float64
    ...

    long_name :

    Snowfall rate from Z using Wolf and Snider (2012)

    units :

    mm/h

    standard_name :

    snowfall_rate

    valid_min :

    0

    valid_max :

    500

    swe_ratio :

    13.699

    A :

    110

    B :

    2

    [766196 values with dtype=float64]

  • snow_rate_ws88diw
    (azimuth, range)
    float64
    ...

    long_name :

    Snowfall rate from Z using WSR 88D High Plains

    units :

    mm/h

    standard_name :

    snowfall_rate

    valid_min :

    0

    valid_max :

    500

    swe_ratio :

    13.699

    A :

    40

    B :

    2

    [766196 values with dtype=float64]

  • snow_rate_m2009_1
    (azimuth, range)
    float64
    ...

    long_name :

    Snowfall rate from Z using Matrosov et al.(2009) Braham(1990) 1

    units :

    mm/h

    standard_name :

    snowfall_rate

    valid_min :

    0

    valid_max :

    500

    swe_ratio :

    13.699

    A :

    67

    B :

    1.28

    [766196 values with dtype=float64]

  • snow_rate_m2009_2
    (azimuth, range)
    float64
    ...

    long_name :

    Snowfall rate from Z using Matrosov et al.(2009) Braham(1990) 2

    units :

    mm/h

    standard_name :

    snowfall_rate

    valid_min :

    0

    valid_max :

    500

    swe_ratio :

    13.699

    A :

    114

    B :

    1.39

    [766196 values with dtype=float64]

  • sweep_number
    ()
    int32
    ...

    long_name :

    Sweep index number 0 based

    units :

    1

    [1 values with dtype=int32]

  • sweep_fixed_angle
    ()
    float32
    ...

    long_name :

    Ray Target Fixed Angle

    units :

    degree

    [1 values with dtype=float32]

  • sweep_mode
    ()
    <U188
    'azimuth_surveillance\x00\x00\x0...

    array('azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance',
          dtype='<U188')

  • nyquist_velocity
    (azimuth)
    float64
    ...

    long_name :

    Nyquist velocity

    units :

    m/s

    standard_name :

    nyquist_velocity

    [1147 values with dtype=float64]

• Attributes: (0)

dt["sweep_0"]["corrected_reflectivity"].plot(x="x",
                                             y="y",
                                             cmap="ChaseSpectral",
                                             vmin=-10,
                                             vmax=30)

<matplotlib.collections.QuadMesh at 0x7f1d4c266320>

Plot along an azimuth with the power of xarray

DBZH = dt["sweep_0"]["corrected_reflectivity"]

# Select the northwest azimuth (315 degrees) to view reflectivity
DBZH.sel(azimuth=315., method='nearest').plot()

[<matplotlib.lines.Line2D at 0x7f1d4c19ef80>]

The power of common data models

Using wradlib - Z(S) estimating snowfall!

See the discussion here for a more thorough literature review of the different relationships, but we can relate the properties of the scatterers to snowfall rates, using a log relationship:

Z = liquid_equivalent_snowfall * A * (S ^ B)

wradlib has a helper accessor to calculate this for this, solving for the snowfall rate in mm/hr, https://docs.wradlib.org/en/stable/zr.html

Here, we use values suitable for the Intermountain West, as this radar is in the Colorado Rockies.

a = 40
b = 2

snowfall = DBZH.wrl.zr.z_to_r(a=a, b=b)

# Update the attributes
snowfall.attrs["standard_name"]  = "snowfall_rate"
snowfall.attrs["long_name"] = "snwofall_rate"

/home/runner/miniconda3/envs/open-radar-pangeo-showcase-2024-dev/lib/python3.10/site-packages/wradlib/zr.py:62: RuntimeWarning: invalid value encountered in sqrt
  return (z / a) ** (1.0 / b)

snowfall.plot(x="x",
              y="y",
              cmap="ChaseSpectral",
              vmin=0,
              vmax=1)

<matplotlib.collections.QuadMesh at 0x7f1d4c018b20>

Add this field back into our datatree!

dt["sweep_0"]["snowfall_rate"] = snowfall

Use Py-ART to grid this up!

radar = pyart.xradar.Xradar(dt)
radar

<xarray.DatasetView> Size: 1kB
Dimensions:              (sweep: 1)
Dimensions without coordinates: sweep
Data variables:
    sweep_group_name     (sweep) <U7 28B 'sweep_0'
    sweep_fixed_angle    (sweep) float32 4B ...
    latitude             float64 8B 38.9
    longitude            float64 8B -106.9
    altitude             float64 8B 3.149e+03
    time_coverage_start  |S192 192B ...
    time_coverage_end    |S192 192B ...
    volume_number        int32 4B ...
    platform_type        |S192 192B ...
    instrument_type      |S192 192B ...
    primary_axis         |S192 192B ...
Attributes:
    Conventions:  CF/Radial instrument_parameters ARM-1.3
    comment:      This is highly experimental and initial data. There are man...
    references:   See XSAPR Instrument Handbook
    source:       Atmospheric Radiation Measurement (ARM) program X-band Scan...
    institution:  U.S. Department of Energy Atmospheric Radiation Measurement...
    history:      created by jrobrien on cirrus127.ccs.ornl.gov at 2022-09-26...

datatree.DataTree

• Groups: (3)
  <xarray.DatasetView> Size: 0B
  Dimensions:  ()
  Data variables:
      *empty*

  radar_parameters

  • Groups: (0)
  • Dimensions:
  • Coordinates: (0)
  • Data variables: (0)
  • Attributes: (0)

  <xarray.DatasetView> Size: 0B
  Dimensions:  ()
  Data variables:
      *empty*

  georeferencing_correction

  • Groups: (0)
  • Dimensions:
  • Coordinates: (0)
  • Data variables: (0)
  • Attributes: (0)

  <xarray.DatasetView> Size: 208MB
  Dimensions:                                   (azimuth: 1147, range: 668)
  Coordinates:
      time                                      (azimuth) datetime64[ns] 9kB 20...
    * range                                     (range) float32 3kB 306.9 ... 4...
      elevation                                 (azimuth) float32 5kB 5.988 ......
    * azimuth                                   (azimuth) float32 5kB 0.05238 ....
      latitude                                  float64 8B 38.9
      longitude                                 float64 8B -106.9
      altitude                                  float64 8B 3.149e+03
      crs_wkt                                   int64 8B 0
      x                                         (azimuth, range) float32 3MB 0....
      y                                         (azimuth, range) float32 3MB 30...
      z                                         (azimuth, range) float32 3MB 3....
  Data variables: (12/38)
      DBZ                                       (azimuth, range) float64 6MB ...
      VEL                                       (azimuth, range) float64 6MB ...
      WIDTH                                     (azimuth, range) float64 6MB ...
      ZDR                                       (azimuth, range) float64 6MB ...
      PHIDP                                     (azimuth, range) float64 6MB ...
      RHOHV                                     (azimuth, range) float64 6MB ...
      ...                                        ...
      snow_rate_m2009_2                         (azimuth, range) float64 6MB ...
      sweep_number                              int32 4B ...
      sweep_fixed_angle                         float32 4B ...
      sweep_mode                                <U188 752B 'azimuth_surveillanc...
      nyquist_velocity                          (azimuth) float64 9kB ...
      snowfall_rate                             (azimuth, range) float64 6MB 0....

  sweep_0

  • Groups: (0)
  • Dimensions:
    • azimuth: 1147
    • range: 668
  • Coordinates: (11)
    • time
      (azimuth)
      datetime64[ns]
      2022-03-14T02:18:06 ... 2022-03-...

      long_name :

      Time in Seconds from Volume Start

      standard_name :

      time

      array(['2022-03-14T02:18:06.000000000', '2022-03-14T02:18:06.000000000',
             '2022-03-14T02:17:35.000000000', ..., '2022-03-14T02:18:06.000000000',
             '2022-03-14T02:18:06.000000000', '2022-03-14T02:18:06.000000000'],
            dtype='datetime64[ns]')

    • range
      (range)
      float32
      306.9 366.8 ... 4.023e+04 4.029e+04

      long_name :

      Range to measurement volume

      units :

      meter

      standard_name :

      projection_range_coordinate

      spacing_is_constant :

      true

      axis :

      radial_range_coordinate

      meters_to_center_of_first_gate :

      -112.6891

      meters_between_gates :

      59.94095

      array([  306.88168,   366.82263,   426.76358, ..., 40167.61   , 40227.555  ,
             40287.496  ], dtype=float32)

    • elevation
      (azimuth)
      float32
      5.988 5.988 5.938 ... 5.988 5.988

      long_name :

      Elevation angle from horizontal plane

      units :

      degree

      axis :

      radial_elevation_coordinate

      standard_name :

      sensor_to_target_elevation_angle

      array([5.987549, 5.987549, 5.93811 , ..., 5.987549, 5.987549, 5.987549],
            dtype=float32)

    • azimuth
      (azimuth)
      float32
      0.05238 0.1128 ... 359.9 360.0

      long_name :

      Azimuth Angle from True North

      units :

      degree

      axis :

      radial_azimuth_coordinate

      standard_name :

      sensor_to_target_azimuth_angle

      array([5.238281e-02, 1.128076e-01, 1.250684e-01, ..., 3.597612e+02,
             3.598821e+02, 3.599755e+02], dtype=float32)

    • latitude
      ()
      float64
      38.9

      long_name :

      Latitude

      units :

      degree_N

      standard_name :

      latitude

      valid_min :

      -90.0

      valid_max :

      90.0

      array(38.89838)

    • longitude
      ()
      float64
      -106.9

      long_name :

      Longitude

      units :

      degree_E

      standard_name :

      longitude

      valid_min :

      -180.0

      valid_max :

      180.0

      array(-106.943214)

    • altitude
      ()
      float64
      3.149e+03

      long_name :

      Altitude

      units :

      m

      standard_name :

      altitude

      array(3149.199951)

    • crs_wkt
      ()
      int64
      0

      crs_wkt :

      PROJCRS["unknown",BASEGEOGCRS["unknown",DATUM["World Geodetic System 1984",ELLIPSOID["WGS 84",6378137,298.257223563,LENGTHUNIT["metre",1]],ID["EPSG",6326]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8901]]],CONVERSION["unknown",METHOD["Modified Azimuthal Equidistant",ID["EPSG",9832]],PARAMETER["Latitude of natural origin",38.898380279541,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8801]],PARAMETER["Longitude of natural origin",-106.943214416504,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8802]],PARAMETER["False easting",0,LENGTHUNIT["metre",1],ID["EPSG",8806]],PARAMETER["False northing",0,LENGTHUNIT["metre",1],ID["EPSG",8807]]],CS[Cartesian,2],AXIS["(E)",east,ORDER[1],LENGTHUNIT["metre",1,ID["EPSG",9001]]],AXIS["(N)",north,ORDER[2],LENGTHUNIT["metre",1,ID["EPSG",9001]]]]

      semi_major_axis :

      6378137.0

      semi_minor_axis :

      6356752.314245179

      inverse_flattening :

      298.257223563

      reference_ellipsoid_name :

      WGS 84

      longitude_of_prime_meridian :

      0.0

      prime_meridian_name :

      Greenwich

      geographic_crs_name :

      unknown

      horizontal_datum_name :

      World Geodetic System 1984

      projected_crs_name :

      unknown

      grid_mapping_name :

      azimuthal_equidistant

      latitude_of_projection_origin :

      38.898380279541016

      longitude_of_projection_origin :

      -106.9432144165039

      false_easting :

      0.0

      false_northing :

      0.0

      array(0)

    • x
      (azimuth, range)
      float32
      0.2789 0.3334 ... -17.13 -17.15

      standard_name :

      east_west_distance_from_radar

      units :

      meters

      array([[ 2.7893224e-01,  3.3341372e-01,  3.8789520e-01, ...,
               3.6491188e+01,  3.6545620e+01,  3.6600048e+01],
             [ 6.0068691e-01,  7.1801394e-01,  8.3534104e-01, ...,
               7.8584595e+01,  7.8701813e+01,  7.8819031e+01],
             [ 6.6603380e-01,  7.9612476e-01,  9.2621547e-01, ...,
               8.7133934e+01,  8.7263901e+01,  8.7393867e+01],
             ...,
             [-1.2714366e+00, -1.5197754e+00, -1.7681143e+00, ...,
              -1.6633513e+02, -1.6658322e+02, -1.6683133e+02],
             [-6.2798256e-01, -7.5064105e-01, -8.7329954e-01, ...,
              -8.2155540e+01, -8.2278084e+01, -8.2400627e+01],
             [-1.3073300e-01, -1.5626796e-01, -1.8180293e-01, ...,
              -1.7103086e+01, -1.7128597e+01, -1.7154108e+01]], dtype=float32)

    • y
      (azimuth, range)
      float32
      305.1 364.7 ... 3.997e+04 4.003e+04

      standard_name :

      north_south_distance_from_radar

      units :

      meters

      array([[  305.09314,   364.6844 ,   424.27563, ..., 39913.676  ,
              39973.21   , 40032.746  ],
             [  305.09265,   364.6838 ,   424.275  , ..., 39913.613  ,
              39973.15   , 40032.684  ],
             [  305.12003,   364.71664,   424.31314, ..., 39917.355  ,
              39976.9    , 40036.438  ],
             ...,
             [  305.0906 ,   364.68137,   424.27213, ..., 39913.344  ,
              39972.88   , 40032.414  ],
             [  305.09262,   364.68375,   424.2749 , ..., 39913.605  ,
              39973.14   , 40032.676  ],
             [  305.09323,   364.6845 ,   424.27576, ..., 39913.688  ,
              39973.223  , 40032.758  ]], dtype=float32)

    • z
      (azimuth, range)
      float32
      3.181e+03 3.188e+03 ... 7.446e+03

      standard_name :

      height_above_ground

      units :

      meters

      array([[3181., 3188., 3194., ..., 7433., 7440., 7446.],
             [3181., 3188., 3194., ..., 7433., 7440., 7446.],
             [3181., 3187., 3193., ..., 7399., 7405., 7411.],
             ...,
             [3181., 3188., 3194., ..., 7433., 7440., 7446.],
             [3181., 3188., 3194., ..., 7433., 7440., 7446.],
             [3181., 3188., 3194., ..., 7433., 7440., 7446.]], dtype=float32)

  • Data variables: (38)
    • DBZ
      (azimuth, range)
      float64
      ...

      long_name :

      Equaivalent_radar_reflectiivity_factor

      units :

      dBZ

      standard_name :

      equivalent_reflectivity_factor

      [766196 values with dtype=float64]

    • VEL
      (azimuth, range)
      float64
      ...

      long_name :

      Radial Doppler Velocity, Positive for Motion Away from Instrument

      units :

      m/s

      standard_name :

      radial_velocity_of_scatterers_away_from_instruments

      [766196 values with dtype=float64]

    • WIDTH
      (azimuth, range)
      float64
      ...

      long_name :

      Spectral Width

      units :

      m/s

      standard_name :

      doppler_spectrum_width

      [766196 values with dtype=float64]

    • ZDR
      (azimuth, range)
      float64
      ...

      long_name :

      Differential Reflectivity

      units :

      dB

      standard_name :

      log_differential_reflectivity_hv

      [766196 values with dtype=float64]

    • PHIDP
      (azimuth, range)
      float64
      ...

      long_name :

      Differential Phase

      units :

      degree

      standard_name :

      differential_phase_hv

      [766196 values with dtype=float64]

    • RHOHV
      (azimuth, range)
      float64
      ...

      long_name :

      Cross-Polar Correlation Ratio

      units :

      1

      standard_name :

      cross_correlation_ratio_hv

      [766196 values with dtype=float64]

    • NCP
      (azimuth, range)
      float64
      ...

      long_name :

      Normalized Coherent Power, also known as SQI

      units :

      1

      standard_name :

      normalized_coherent_power

      [766196 values with dtype=float64]

    • DBZhv
      (azimuth, range)
      float64
      ...

      long_name :

      Equivalent Reflectivity Factor HV

      units :

      dBZ

      standard_name :

      equivalent_reflectivity_factor_hv

      [766196 values with dtype=float64]

    • cbb_flag
      (azimuth, range)
      float64
      ...

      long_name :

      Cumulative Beam Block Fraction Flag

      units :

      1

      comment :

      Cumulative beam block flag due to terrain.

      [766196 values with dtype=float64]

    • sounding_temperature
      (azimuth, range)
      float32
      ...

      long_name :

      Interpolated profile

      units :

      degC

      standard_name :

      interpolated_profile

      [766196 values with dtype=float32]

    • height
      (azimuth, range)
      float32
      ...

      long_name :

      Height of radar beam

      units :

      m

      standard_name :

      height

      [766196 values with dtype=float32]

    • signal_to_noise_ratio
      (azimuth, range)
      float64
      ...

      long_name :

      Signal to Noise Ratio

      units :

      dB

      standard_name :

      signal_to_noise_ratio

      [766196 values with dtype=float64]

    • velocity_texture
      (azimuth, range)
      float64
      ...

      long_name :

      Mean dopper velocity

      units :

      m/s

      standard_name :

      radial_velocity_of_scatterers_away_from_instrument

      [766196 values with dtype=float64]

    • gate_id
      (azimuth, range)
      int64
      ...

      long_name :

      Classification of dominant scatterer

      units :

      1

      notes :

      0:multi_trip,1:rain,2:snow,3:no_scatter,4:melting,5:clutter,6:terrain_blockage

      valid_max :

      6

      valid_min :

      0

      flag_values :

      0, 1, 2, 3, 4, 5, 6

      flag_meanings :

      multi_trip rain snow no_scatter melting clutter terrain_blockage

      [766196 values with dtype=int64]

    • simulated_velocity
      (azimuth, range)
      float64
      ...

      long_name :

      Simulated mean doppler velocity

      units :

      m/s

      standard_name :

      radial_velocity_of_scatterers_away_from_instrument

      [766196 values with dtype=float64]

    • corrected_velocity
      (azimuth, range)
      float64
      ...

      long_name :

      Corrected mean doppler velocity

      units :

      m/s

      standard_name :

      corrected_radial_velocity_of_scatterers_away_from_instrument

      valid_min :

      -79.5

      valid_max :

      79.5

      [766196 values with dtype=float64]

    • unfolded_differential_phase
      (azimuth, range)
      float64
      ...

      long_name :

      Unfolded differential propagation phase shift

      units :

      degree

      standard_name :

      differential_phase_hv

      [766196 values with dtype=float64]

    • corrected_differential_phase
      (azimuth, range)
      float64
      ...

      long_name :

      Corrected differential propagation phase shift

      units :

      degree

      standard_name :

      differential_phase_hv

      valid_min :

      0.0

      valid_max :

      400.0

      [766196 values with dtype=float64]

    • filtered_corrected_differential_phase
      (azimuth, range)
      float64
      ...

      long_name :

      Filtered Corrected Differential Phase

      units :

      degree

      standard_name :

      differential_phase_hv

      valid_min :

      0.0

      valid_max :

      400.0

      [766196 values with dtype=float64]

    • corrected_specific_diff_phase
      (azimuth, range)
      float64
      ...

      long_name :

      Specific differential phase (KDP)

      units :

      degrees/km

      standard_name :

      specific_differential_phase_hv

      [766196 values with dtype=float64]

    • filtered_corrected_specific_diff_phase
      (azimuth, range)
      float64
      ...

      long_name :

      Filtered Corrected Specific differential phase (KDP)

      units :

      degrees/km

      standard_name :

      specific_differential_phase_hv

      [766196 values with dtype=float64]

    • corrected_differential_reflectivity
      (azimuth, range)
      float64
      ...

      long_name :

      Corrected differential reflectivity

      units :

      dB

      standard_name :

      corrected_log_differential_reflectivity_hv

      [766196 values with dtype=float64]

    • corrected_reflectivity
      (azimuth, range)
      float64
      6.64 10.14 5.31 ... nan nan nan

      long_name :

      Corrected reflectivity

      units :

      dBZ

      standard_name :

      corrected_equivalent_reflectivity_factor

      array([[ 6.64    , 10.139999,  5.31    , ...,       nan,       nan,       nan],
             [ 6.59    , 10.01    ,  6.22    , ...,       nan,       nan,       nan],
             [ 5.35    ,  9.389999,  9.61    , ...,       nan,       nan,       nan],
             ...,
             [ 7.54    ,  8.639999,  5.04    , ...,       nan,       nan,       nan],
             [ 9.38    , 10.62    ,  5.34    , ...,       nan,       nan,       nan],
             [ 9.17    , 10.42    ,  4.79    , ...,       nan,       nan,       nan]])

    • height_over_iso0
      (azimuth, range)
      float32
      ...

      long_name :

      Height of radar beam over freezing level

      units :

      m

      standard_name :

      height

      [766196 values with dtype=float32]

    • specific_attenuation
      (azimuth, range)
      float64
      ...

      long_name :

      Specific attenuation

      units :

      dB/km

      standard_name :

      specific_attenuation

      valid_min :

      0.0

      valid_max :

      1.0

      [766196 values with dtype=float64]

    • path_integrated_attenuation
      (azimuth, range)
      float64
      ...

      long_name :

      Path Integrated Attenuation

      units :

      dB

      [766196 values with dtype=float64]

    • specific_differential_attenuation
      (azimuth, range)
      float64
      ...

      long_name :

      Specific Differential Attenuation

      units :

      dB/km

      [766196 values with dtype=float64]

    • path_integrated_differential_attenuation
      (azimuth, range)
      float64
      ...

      long_name :

      Path Integrated Differential Attenuation

      units :

      dB

      [766196 values with dtype=float64]

    • rain_rate_A
      (azimuth, range)
      float64
      ...

      long_name :

      Rainfall Rate from Specific Attenuation

      units :

      mm/hr

      standard_name :

      rainfall_rate

      comment :

      Rain rate calculated from specific_attenuation, R=43.5*specific_attenuation**0.79, note R=0.0 where norm coherent power < 0.4 or rhohv < 0.8

      valid_min :

      0.0

      valid_max :

      400.0

      [766196 values with dtype=float64]

    • snow_rate_ws2012
      (azimuth, range)
      float64
      ...

      long_name :

      Snowfall rate from Z using Wolf and Snider (2012)

      units :

      mm/h

      standard_name :

      snowfall_rate

      valid_min :

      0

      valid_max :

      500

      swe_ratio :

      13.699

      A :

      110

      B :

      2

      [766196 values with dtype=float64]

    • snow_rate_ws88diw
      (azimuth, range)
      float64
      ...

      long_name :

      Snowfall rate from Z using WSR 88D High Plains

      units :

      mm/h

      standard_name :

      snowfall_rate

      valid_min :

      0

      valid_max :

      500

      swe_ratio :

      13.699

      A :

      40

      B :

      2

      [766196 values with dtype=float64]

    • snow_rate_m2009_1
      (azimuth, range)
      float64
      ...

      long_name :

      Snowfall rate from Z using Matrosov et al.(2009) Braham(1990) 1

      units :

      mm/h

      standard_name :

      snowfall_rate

      valid_min :

      0

      valid_max :

      500

      swe_ratio :

      13.699

      A :

      67

      B :

      1.28

      [766196 values with dtype=float64]

    • snow_rate_m2009_2
      (azimuth, range)
      float64
      ...

      long_name :

      Snowfall rate from Z using Matrosov et al.(2009) Braham(1990) 2

      units :

      mm/h

      standard_name :

      snowfall_rate

      valid_min :

      0

      valid_max :

      500

      swe_ratio :

      13.699

      A :

      114

      B :

      1.39

      [766196 values with dtype=float64]

    • sweep_number
      ()
      int32
      ...

      long_name :

      Sweep index number 0 based

      units :

      1

      [1 values with dtype=int32]

    • sweep_fixed_angle
      ()
      float32
      ...

      long_name :

      Ray Target Fixed Angle

      units :

      degree

      [1 values with dtype=float32]

    • sweep_mode
      ()
      <U188
      'azimuth_surveillance\x00\x00\x0...

      array('azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance\x00\x00\x00\x00azimuth_surveillance',
            dtype='<U188')

    • nyquist_velocity
      (azimuth)
      float64
      ...

      long_name :

      Nyquist velocity

      units :

      m/s

      standard_name :

      nyquist_velocity

      [1147 values with dtype=float64]

    • snowfall_rate
      (azimuth, range)
      float64
      0.4074 0.5035 0.3643 ... nan nan

      standard_name :

      snowfall_rate

      long_name :

      snwofall_rate

      short_name :

      RATE

      units :

      mm h-1

      array([[0.40743097, 0.50348782, 0.36434873, ...,        nan,        nan,
                     nan],
             [0.40589406, 0.50024994, 0.39433488, ...,        nan,        nan,
                     nan],
             [0.36571847, 0.48451005, 0.49015303, ...,        nan,        nan,
                     nan],
             ...,
             [0.43416587, 0.46475799, 0.35496479, ...,        nan,        nan,
                     nan],
             [0.484252  , 0.51526692, 0.36537651, ...,        nan,        nan,
                     nan],
             [0.47880059, 0.51039201, 0.34604913, ...,        nan,        nan,
                     nan]])

  • Attributes: (0)

• Dimensions:
  • sweep: 1
• Coordinates: (0)
• Data variables: (11)
  • sweep_group_name
    (sweep)
    <U7
    'sweep_0'

    array(['sweep_0'], dtype='<U7')

  • sweep_fixed_angle
    (sweep)
    float32
    ...

    long_name :

    Ray Target Fixed Angle

    units :

    degree

    [1 values with dtype=float32]

  • latitude
    ()
    float64
    38.9

    long_name :

    Latitude

    units :

    degree_N

    standard_name :

    latitude

    valid_min :

    -90.0

    valid_max :

    90.0

    array(38.89838)

  • longitude
    ()
    float64
    -106.9

    long_name :

    Longitude

    units :

    degree_E

    standard_name :

    longitude

    valid_min :

    -180.0

    valid_max :

    180.0

    array(-106.943214)

  • altitude
    ()
    float64
    3.149e+03

    long_name :

    Altitude

    units :

    m

    standard_name :

    altitude

    array(3149.199951)

  • time_coverage_start
    ()
    |S192
    ...

    long_name :

    UTC time of first ray in the file

    units :

    unitless

    [1 values with dtype=|S192]

  • time_coverage_end
    ()
    |S192
    ...

    long_name :

    UTC time of last ray in the file

    units :

    unitless

    [1 values with dtype=|S192]

  • volume_number
    ()
    int32
    ...

    long_name :

    Volume number

    units :

    unitless

    [1 values with dtype=int32]

  • platform_type
    ()
    |S192
    ...

    long_name :

    Platform type

    [1 values with dtype=|S192]

  • instrument_type
    ()
    |S192
    ...

    long_name :

    Instrument type

    [1 values with dtype=|S192]

  • primary_axis
    ()
    |S192
    ...

    long_name :

    Primary axis

    [1 values with dtype=|S192]

• Attributes: (6)

  Conventions :

  CF/Radial instrument_parameters ARM-1.3

  comment :

  This is highly experimental and initial data. There are many known and unknown issues. Please do not use before contacting the Translator responsible scollis@anl.gov

  references :

  See XSAPR Instrument Handbook

  source :

  Atmospheric Radiation Measurement (ARM) program X-band Scanning ARM Precipitation Radar (XSAPR)

  institution :

  U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Climate Research Facility

  history :

  created by jrobrien on cirrus127.ccs.ornl.gov at 2022-09-26T13:18:32.369353 using Py-ART

grid = pyart.map.grid_from_radars(
    [radar],
    grid_shape=(21, 161, 161),
    grid_limits=(
        (
            0.0,
            5_000,
        ),
        (-20_000., 20_000.),
        (-20_000, 20_000.),
    ),
)

ds = grid.to_xarray()

ds.snowfall_rate.isel(z=1).plot(x='lon', y='lat')

<matplotlib.collections.QuadMesh at 0x7f1d4c22a8f0>

Danger

Not every method has been implemented for the xradar-radar object bridge. If you find an issue, open an issue!

Visualization fun

Let’s use some holoviz tools!

Create an Interactive PPI Plot

proj_crs = xd.georeference.get_crs(dt["sweep_0"].ds)
cart_crs = ccrs.Projection(proj_crs)

ref_plot = dt["sweep_0"]["corrected_reflectivity"].hvplot.quadmesh(x="x",
                                                        y="y",
                                                        cmap="ChaseSpectral",
                                                        rasterize=True,
                                                        height=500,
                                                        width=600,
                                                        title = "Refletivity (dBz)",
                                                        clim=(-10, 30))
ref_plot

snow_plot = dt["sweep_0"]["snowfall_rate"].hvplot.quadmesh(x="x",
                                                            y="y",
                                                            cmap="ChaseSpectral",
                                                            rasterize=True,
                                                            height=500,
                                                            width=600,
                                                            title = "Snowfall rate (mm/hr)",
                                                            clim=(0, 1))
snow_plot

(snow_plot + ref_plot).cols(1)

---

Summary

Within this notebook, we looked at the current methods of working with radar data in Python - using Py-ART and xradar!

What’s next?

Stay tuned - following along with the:

• xradar repository

• Py-ART repository

• openradar discourse

Resources and references

• The Python ARM Radar Toolkit (Py-ART)

  • JJ Helmus and SM Collis; JORS 2016; doi: 10.5334/jors.119

• xradar

  • Grover, Mühlbauer, Goudenhoofdt, Syed, Ladino; Zenodo 2024; doi: 10.5281/zenodo.10065754

• SAIL Radar Data

  • Atmospheric Radiation Measurement (ARM) user facility. 2022. CSU X-Band Precip Radar (XPRECIPRADAR) PPI Corrected Moments to Antenna Coord (XPRECIPRADARCMACPPI). 2022-03-01 to 2023-03-31, ARM Mobile Facility (GUC) Gunnison, CO; Supplemental Facility 2 (S2). Compiled by R. Jackson, Z. Sherman, S. Collis, J. O’Brien, M. Grover, B. Raut, A. Theisen, M. Tuftedal and D. Feldman. ARM Data Center. Data set accessed 2024-04-02 at http://dx.doi.org/10.5439/1883164.